Ophthalmic formulations and related methods

ABSTRACT

This disclosure is directed to ophthalmic suspensions for dry eye and other ocular indications that provide long-lasting on eye benefits. The disclosure provides methods of increasing lipid layer thickness and methods of lubricating an eye. The disclosure also provides methods of maintaining integrity of an eye&#39;s tear film layers which increases the eye&#39;s lipid layer thickness and methods of recreating or building one or more layers of an eye&#39;s tear film.

FIELD

The present disclosure provides a long-lasting ophthalmic suspension forocular therapy for dry eye and other ocular indications. The ophthalmicsuspension described herein provide relief for dry eye that lasts two toten times longer on the eye than currently marketed products.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/895,513 filed Aug. 25, 2022, which is a divisional of U.S.application Ser. No. 17/689,212 filed Mar. 8, 2022 the contents of whichare each incorporated herein in their entirety.

BACKGROUND

The tear film is produced by secretions of the different glands of theeye during normal blinking. These secretions or components makeup ahealthy and stable tear film. The aqueous portion of the tear isproduced by primarily the lacrimal gland activated by blinking. Theexternal tear film layer is the lipid layer which is excreted duringblinking primarily from the Meibomian glands located in the eye lids.The lipid layer provides a protective layer on top of the tear filmdesigned to reduce the evaporation of the aqueous of the tear film.Thinning of the lipid layer adds increased evaporation of the aqueouslayer resulting in a dry eye on the corneal surface between blinks. Suchdry eye patients tear film rate of evaporation increases by 30% to 38%at less than 50% relative humidity These collective of secretions fromthe lacrimal and Meibomian glands along with eye lid providing a wipereffect from normal blinking provides a normal, long lasting, and stableocular tear film. While the normal production of ingredients continuallyrepair and replaces the tear film, the loss of key ingredients due todysfunction or non-secretions makes the tear film unstable and rapidlyleads to loss of the tear film structure resulting in dry eye.

The tear film protects, lubricates, nourishes and cleanses the ocularsurface. An important role is to prevent dehydration of the underlyingcornea and the tissue of the conjunctiva as well as to provide alubricated surface during a blink. The tear film serves in a number ofdifferent functions. One of the most important functions of the tearfilm is its role reducing evaporation from the surface of the eye,thereby preventing corneal and conjunctival drying. Failure of the tearfilm to keep the eye adequately hydrated and lubricated can result inepithelial cell damage and inflammation. This, in turn may result insevere discomfort or pain and even severe corneal damage. The tear filmlubricates the eyelids ensuring smooth and comfortable blinking. If thesurface of the cornea and eyelid are not sufficiently smooth orlubricated, abrasive damage may result and cause similar problems ofthose of corneal and conjunctival drying as mentioned above and has beendescribed as lid wiper epitheliopathy. Since the cornea is an avascularconstruct, the tear film contains nutrients to nourish the cornealepithelium and removes cellular waste products and debris. It alsosupplies oxygen to, and removes carbon dioxide from, the corneal andconjunctival epithelia. If the cornea becomes malnourished, bloodvessels may grow into it in order to provide the necessary nutrients.These vessels can obstruct vision and are characteristic of very severedry eye conditions.

The tear film contains antibacterial and anti-viral substances whichdefend the eye against infection. Tears are buffered and are able toneutralize mild acids and bases thereby enabling the eye to tolerate theinstillation of substances with a pH range of 6.6 to 7.8. The tear filmrefracts (bends) light and aids visual acuity by forming a smooth, clearoptical surface over the cornea (thereby eliminating minute surfaceirregularities in the corneal epithelium). The tear film has arefractive index ranging between 1.3345 and 1.3360 (compared was anIndex of 1.0 for air).

The tear film is understood to be composed of five distinct layers whereeach perform a key function in maintaining the tear film. An outer(oily) lipid layer which lubricates the movement of the eye lid andreduces evaporation of the aqueous (watery) layer. The next layer thatmakes up the largest portion of the tear film is the aqueous (watery)layer that hydrates and provides nutrients to the avascular cornea whileremoving cellular by product and debris. Finally, an inner mucin layerexcreted by the cornea that lowers the surface tension of the tear filmto enable uniform spreading across the surface of the eye. An outerinterstitial layer is located between the lipid layer and aqueous layer.An inner interstitial layer is located between the aqueous layer andmucin layer.

A continuous basal secretion of the tear components at all times of theday and night normally ensures the tear film provides adequatelubrication and protection for most environments. However, theproduction and maintenance of the tear film does not simply rely on theproduction of sufficient quantities of tears. The quality (i.e., thecomposition) of the tears and the blinking process also play animportant role in maintaining a healthy tear film.

Normal tears with the correct balance of lipid, aqueous and mucincomponents combined during blinking form a stable and protective tearfilm. Between blinks, the tear film thins due to evaporation and lipidmolecules from the outer layer begin to migrate through the aqueouslayer towards the mucin layer. The aqueous portion of the tear also isexchanged on the eye approximately 16% by volume every minute where thelipid layer is exchanged at a rate of approximately 2% per minute on theeye. Contamination of the mucin layer by the lipid layer increases thesurface tension of the tear film and eventually causes it to rupture(break-up) and bead up on the surface of the cornea forming a dry spot.A subsequent blink normally repairs this rupture by removing the lipidcontaminants from the mucin layer and restoring a normal aqueous layer.Repeated rupture, however, can cause loss of the mucin layer and showstaining when observed using fluorescein.

In the balance between the tear film components is upset as a result ofaging, diseases, gland malfunction, drugs, preservatives in ophthalmicpreparations or the wearing of contact lenses, failure to blinkappropriately and lid closure or sealing issues the tear film becomesless stable and may break up in only a few seconds (i.e., before thenext blink). When this occurs the break-up time is shorter than theinterval blinks (whether because of an adequate tear film or inadequateblinking), dry spots develop on the ocular surface of the eye, and thisbecomes the first stage in the development of ocular surface disease ordry eye. Ideally the breakup time should equal or be longer that thenormal blink interval.

Loss of the tear film structure leads to dry eye which is an ophthalmicmedical condition currently exhibited in over 350 million patientsworldwide, and over 50 million in the US: equivalent to 15% of the USpopulation. The discomfort resulting from a dry eye condition mayinclude ocular dryness, grittiness, burning, soreness, scratching, orforeign body reaction. The degree of discomfort is dependent upon thesubject and the condition of the subject. The leading cause of dry eyecomes from the loss of the lipid layer due to the dysfunction of theMeibomian glands estimated to be as high as 86% of all dry eye. Changesin the composition are reflected in the meibum being produced as athick/semisolid material and/or the loss of the glands producing themeibum. Also, little is known about the importance of variousconstituents in the formation of the lipid layer although differencehave been discussed by many authors. The importance of the lipid layerin the maintenance of the tear film is well studied showing that iscritical in preventing the loss of the aqueous layer by evaporation. Thethinning of the lipid layer is believed to enhance the symptoms of dryeye resulting from the evaporation of the aqueous component of the tearfilm.

The most common treatment for dry eye involves temporary alleviation ofdry eye symptoms by topical application of an artificial tear substitutethat provide a volume of liquid to the surface of the eye andneighboring tissues, e.g., eyelids, cornea. Typical commerciallyavailable tear substitute compositions comprise water soluble polymersolutions. Examples of such solutions include saline solutions ofpolyvinyl alcohol, hydroxypropylmethyl cellulose, or carboxymethylcellulose. U.S. Pat. No. 4,421,748 teaches an artificial tearcomposition comprising an aqueous hypotonic solution of lecithin and aviscosity-adjusting agent such as a solution of a soluble cellulose. Anaqueous tear film extends over the ocular surface and maintains a moistand lubricated ocular surface. It is also known that dehydration ofmoisture from the eye may result in discomfort. Further, compositionsare available in the market intended for dry eye treatment. Commerciallyavailable compositions are primarily aqueous materials that supplementthe tear film by adding a film of a water soluble polymer over thesurface of the eye. These films are short lived and provide limitedrelief.

A number of improved compositions for dry eye treatment are disclosed inU.S. Pat. Nos. 4,914,088; 5,278,151; 5,294,607; 5,578,586, and9,161,905, each incorporated herein by reference for its teaching of howto form an oil film over the surface of the eye including compositionsand uses. U.S. Pat. No. 4,914,088 teaches the use of certain chargedphospholipids for the treatment of dry eye symptoms. The addition of acharged phospholipid to the eye is believed to assist in replicating thetear film that would naturally occur in the eye. In accordance with thepatent, the phospholipid composition, preferably in the form of anaqueous emulsion, is topically applied to the eye where it is believedto disperse over the ocular surface and form a film that replicates alipid layer that would be formed by the spreading of a naturallyoccurring lipid excreted principally from the Meibomian glands duringblinking. Because the phospholipid, when applied to the eye carries anet negative charge, it is believed that aligned molecules repel eachother preventing complex aggregate formation thereby resulting in astable phospholipid interface between the lipid and aqueous phase. Thepatent theorizes that the film formed from the charged phospholipidassists in the formation of a barrier film reducing evaporation of theaqueous layer, thereby preserving the tear film. Others have theorizedthat the phospholipid also functioned as a surfactant maintaining theemulsion stability.

The above referenced U.S. Pat. Nos. 5,278,151; 5,294,607; 5,578,586;9,279,095; and 9,375,401 disclose additional improvements in dry eyetreatment. In these patents, the dry eye treatment composition of U.S.Pat. No. 4,914,088 is improved by the addition of an oil to the eyetreatment composition, preferably a non-polar oil such as mineral oilcomprised of hydrocarbon ingredients. The oil is added to improve theperformance of a dry eye treatment composition by increasing thelongevity of the tear film formed on the eye as a consequence of theformation of an oil film over the ocular surface that functions as anevaporation barrier—i.e., by providing and/or thickening the dehydrationbarrier (the oil layer) on the outer surface of the tear film. Thus, theoil increases the efficacy of the dry eye treatment solution and reducesperformance variability from subject to subject. It also supplements theoils provided from the Meibomian gland which in many cases of dry eyedoes not provide sufficient oils to provide an adequate lipid tearlayer. A preferred embodiment disclosed in the above referenced patentsis a dry eye treatment composition comprising a meta stable oil-in-wateremulsion where the water phase includes the charged phospholipidbelieved to function both as an emulsifier and as a surfactant thatassists in spreading of the oil over the eye to form a non-blurring filmbonding of the oil to the aqueous layer of the tear film. The emulsionis desirably “meta” stable so that when the emulsion is applied to theeye, it will rapidly break and spread over the ocular surface when itfirst comes into contact with the ocular environment.

U.S. Pat. Nos. 5,371,108, 5,278,151 and U.S. Patent Publication No2016/03389952 to Korb teach a method or formulation for creating anemulsion or gel comprising oil and wax to form a tear film on the ocularsurface to prolong the residence time of oil. The wax-containing gel hasnot, however, been produced and marketed commercially because of thedifficulty in homogenizing the wax in such a way that does not inducevisual blurring beyond what would be acceptable by most consumers.Specifically, autoclaving to sterilize the wax-containing formulationleads to increased particle size which leads to irritation and blurredvision. Gels are semi-solid formulations with high viscosity. Incontrast, the present disclosure is directed to metastable emulsionsthat behave as flowing liquids at room temperature. Emulsions behave asliquids and as such do not exhibit a static internal structure or havehigh viscosity. Korb also utilizes preservatives at levels that areknown to be toxic to cornea cells upon administration and does notdisclose a vehicle that would exhibit a long lasting dwell time

A number of ophthalmic formulations and compositions of use note the useof Zeta potential and are disclosed in WO2016209555, WO2015057847,WO2011098578, WO2011084509, WO03053405, US2012328702, US2012225834, andU.S. Pat. Nos. 7,060,285, 9,827,191, 8,298,569, 7,893,040, 7,834,172,and 10,137,083 each incorporated herein by reference for its teaching ofthe use of Zeta potential.

Current commercially available products, including oil and wateremulsion products, often supplement one or more layers of the tear filmthrough various combinations of oils, aqueous solutions, andmucomimetics. These lipid emulsions provide sufficient lubrication andprevention against desiccation, but they remain inadequate in terms oftheir ability to remain on the eye and provide lasting relief, which isthe most desired clinical result. Additionally, these compositions failto fully rebuild the tear film, causing the layers to lose their naturalstability on the surface of the eye and thus have limited relief due totheir on-eye dwell time being less than 30 minutes. Without connectivityto each subsequent layer of the film, the lipid, aqueous, and mucinlayers, whether natural, artificial or some combination thereof, tend tobe expressed in a period of time too short to provide lasting comfortfrom the symptoms of dry eye. FIG. 1 provides an enlarged view of theeye and the components of the layers and interfaces of the tear film.The normal tear film is 3-6 μM thick. The two insets with lines to thetear film show enlarged views of the lipid/aqueous interface and theaqueous/mucin interface. The third inset shows the thinning of thelayers and interfaces associated with dry eye. In particular, it showsthe thinning of (i) the aqueous layer, (ii) the unbound mucin layer, and(iii) the bound mucin layer on the surface of the corneal epithelialcells. Existing products do not stabilize the different layers andinterfaces of the tear film including the lipid layer. Thus, theexisting products do not create a stable lipid layer and provide longterm benefits.

SUMMARY OF THE DISCLOSURE

The human eye's tear film includes the three distinct layers and recentlearning and research has determined that there are two additionallayers of the tear film being interstitial layers. These interstitiallayers of the tear film are from other glands in the eyelid differentfrom the lachrymal and Meibomian Gland of the eyelid. These interstitiallayers excrete ingredients that provide a healthy, normal, and stabletear film. These glands include the glands of Krause, Wolfring, Moll andHeine that excrete wax, wax esters as well as additional surfactants andchemical agents that enhance the Velcro effect of the interface betweenthe tear film layers as well as build and thicken the tear film toreduce tear film evaporation. The two interstitial layers, each performa key function in maintaining the tear film. In total, the tear filmincorporates five layers with the outer (oily) lipid layer excreted bythe Meibomian gland. The first interstitial layer is excreted by theMeibomian gland and glands of Wolfring, Krause, Moll and Heine includeanionic polar phospholipids (i.e., connects the lipid layer to theaqueous layer), wax esters and surfactants (i.e., thickens and enhancesthe lipid layer and interstitial attachment) that connect the lipidlayer to the aqueous layer of the tear film to maintain a stable tearfilm. The next layer that makes up the largest portion of the tear filmis the aqueous (watery) layer that hydrates and provides nutrients tothe avascular cornea while removing cellular by product and debris. Thesecond interstitial layer excreted by the glands of Wolfring, Krause,Moll and Heine is made of wax esters and surfactants that thicken theaqueous and enhance the connection to the corneal secreted mucin whichconnects the aqueous layer to the cornea to maintain a stable tear film.Finally, an inner mucin layer excreted by the cornea is attached to thecornea and lowers the surface tension of the tear film to enable uniformspreading of the tear film across the surface of the eye. The wax andwax esters as well as surfactants and other agents that, in combinationwith the Meibomian gland that excrete lipids, and the lachrymal glandaqueous secretions with lip wiper effect of the eyelid due to normalblinking action, builds a normal, stable and long lasting ocular tearfilm. Thus, the addition of wax esters and their partial hydrolysisproducts, such as beeswax and its normal distribution throughout thevarious phases of the suspension has the same effect of improving theefficacy of the composition by allowing the lubricating elements toremain on the eye for an extended period of time similar to a normaltear film.

Disclosed herein are ophthalmic suspensions that mimic natural tear filmincluding the three distinct layers and the two interstitial layers torebuild or otherwise increase the thickness of the eye's lipid layer foran extended period thereby reducing tear film evaporation andmaintaining a normal ocular tear structure in the eye. The ophthalmicsuspensions provided herein may perform as substitutes for each tearfilm layer (lipid, aqueous, interstitials and mucin) that enhance thetear film, improving the tear film's natural function to createsignificantly longer lasting on eye residence time and improved patientcomfort. By providing a longer lasting effect on the eye, fewerapplications or drops are required to be used by a patient in need oftreatment. By substituting the lipid (outer) layer, enhancing theaqueous (middle) layer, mimicking the mucin (inner) layer andincorporating the interstitial layers, the present ophthalmicsuspensions mimic the natural tears and perform as authentic artificialtears.

Ophthalmic suspensions are provided that include emulsified oil-in-watersuspensions that contain wax esters, or a suitable combination of waxesters, surfactants and other components as provided herein that mimicthe body's natural tear film as well as provide a tear film thatmaintains its structure on the eye for extended periods of time.

According to one aspect, the present disclosure provides an ophthalmicsuspension that includes: i) an aqueous phase comprising water and oneor more components selected from the group consisting of at least onewax ester, at least one anionic polar surfactant, at least one nonionicsurfactant, at least one salt, and at least one phosphate; and ii) anoil phase comprising at least one mineral oil and, optionally, at leastone wax ester. According to one embodiment, the wax ester exhibits amean particle size that is determined via a Microtrac particle analyzer.The wax ester exhibits a mean particle size of at least about 2.0microns. According to one embodiment, the wax ester exhibits a meanparticle size distribution of at least about 2.0 microns to about 20.0microns. According to one embodiment, the wax ester exhibits a meanparticle size distribution of at least about 5.0 microns. According toone embodiment, the ophthalmic suspension has an osmolality of fromabout 245 mOsmol/kg to about 315 mOsmol/kg. According to one embodiment,the ophthalmic suspension is formulated as a free flowing emulsifiedsuspension at about 30° C. According to one embodiment, the wax ester ispresent in a concentration of about 0.8 weight percent to about 1.2weight percent. According to one embodiment, the wax ester is a naturalbeeswax. According to one embodiment, the wax ester is a syntheticbeeswax. According to one embodiment, the ophthalmic suspension exhibitsa negative zeta potential of from about −60 mV to about −110 mV.According to one embodiment, the ophthalmic suspension exhibits an ionicmobility of from about −5.9 (μms)/(V/cm) to about −7.4 (μms)/(V/cm).According to one embodiment, the oil is a mixture of a lightweightmineral oil and a heavy weight mineral oil. According to one embodiment,the lightweight mineral oil exhibits a kinetic viscosity of from about3.0 mm²s⁻¹ to about 34.4 mm²s⁻¹ at 40° C. and the heavy weight mineraloil exhibits a viscosity of kinetic viscosity of from about 34.5 mm²s⁻¹to about 150 mm²s⁻¹ at 40° C. According to one embodiment, theophthalmic suspension further includes an anionic polar surfactantcomprising a mixture of a polysorbate non-ionic surfactant at aconcentration of about 0.35 to about 0.45 weight percent and an anionicpolar dimyristoylphosphatidylglycerol at a concentration of about 0.35to about 0.55 weight percent. According to one embodiment, theophthalmic suspension is packaged as a sterile multi-use or sterilesingle use container. According to one embodiment, the ophthalmicsuspension is packaged in a multi-dose non-preserved (MDNP) container ora container including at least one preservative. According to oneembodiment, the ophthalmic suspension increases lipid layer thickness byat least 20 nanometers at five minutes after administration. Accordingto one embodiment, the ophthalmic suspension increases lipid layerthickness by at least 20 nanometers at 60 minutes after administration.According to one embodiment, the ophthalmic suspension increases lipidlayer thickness by net of control of at least 25 nanometers at fiveminutes after administration. According to one embodiment, theophthalmic suspension increases lipid layer thickness by at least 20nanometers at four hours after administration. According to oneembodiment, the ophthalmic suspension increases lipid layer thickness bynet of control of at least 25 nanometers at four hours afteradministration.

According to another aspect, a method of increasing the lipid layerthickness is provided. The method includes the step of administering anophthalmic suspension as provided herein to an eye of a patient in needof treatment. According to one embodiment, the lipid layer thickness isincreased from baseline by at least 20 nm within five minutes ofadministration. According to one embodiment, the lipid layer thicknessis increased from baseline by at least 20 nm at four hours afteradministration. According to one embodiment, the lipid layer thicknessis increased from baseline by at least 25 nm at four hours afteradministration.

According to one aspect, a method for lubricating an eye is provided.The method includes the step of administering to the eye an ophthalmicsuspension as provided herein to an eye of a patient in need oftreatment. According to one embodiment, the ophthalmic suspensionrecreates or rebuilds one or more layers of the eye's tear film andmaintains integrity of the tear film for over 60 minutes. According toone embodiment, the ophthalmic suspension recreates or rebuilds one ormore layers of the eye's tear film and maintains integrity of the tearfilm for over 90 minutes. According to one embodiment, the ophthalmicsuspension recreates or rebuilds one or more layers of the eye's tearfilm and maintains integrity of the tear film for over 120 minutes.According to one embodiment, the ophthalmic suspension recreates orrebuilds one or more layers of the eye's tear film and maintainsintegrity of the tear film for over 150 minutes.

According to one aspect, a method for alleviating symptoms of dry eye isprovided. The method includes the step of administering to the eye anophthalmic suspension as provided herein to an eye of a patient in needof treatment.

According to one aspect, a method of maintaining integrity of an eye'stear film layers which increases the eye's lipid layer thickness isprovided. The method includes the step of administering an ophthalmicsuspension as provided herein to an eye of a patient in need oftreatment. According to one embodiment, the integrity of the tear filmis maintained and lipid layer thickness is increased by at least 20 nmat 60 minutes after administration.

According to one aspect, a method of recreating or building one or morelayers of an eye's tear film is provided. The method includes the stepof administering an ophthalmic suspension as provided herein to an eyeof a patient in need of treatment. Upon administration, the ophthalmicsuspension recreates or rebuilds the one or more layers of the eye'stear film.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an enlarged view of the tear film with the differentregions. The normal tear film is 3-6 microns thick. The figure shows thelipid layer, the lipid/aqueous interface, the aqueous layer, theaqueous/mucin interface, the mucin layer, and the cornea. Two of theinsets show enlarged views of the lipid/aqueous interface and theaqueous/mucin interface. The third inset shows the thinning of thelayers and interfaces associated with dry eye. In particular, the thirdinset shows the thinning of (i) the aqueous layer, (ii) the unboundmucin layer, and (iii) the bound mucin layer which is bound the surfaceof the corneal epithelial cells. Methodologies to evaluate tear film arefurther provided in U.S. Ser. No. 16/708,120 (U.S. Pub. No.2020/0179281), the entire contents of which are incorporated herein byreference.

DETAILED DESCRIPTION OF THE DISCLOSURE

While the following terms are believed to be well understood by one ofordinary skill in the art, the following definitions are set forth tofacilitate explanation of the presently disclosed subject matter.

As used herein, the terms “about” and/or “approximately” may be used inconjunction with numerical values and/or ranges. The term “about” isunderstood to mean those values near to a recited value. Alternatively,depending on the context, the term “about” may mean±one half a standarddeviation, ±one standard deviation, or ±two standard deviations.Furthermore, the phrases “less than about [a value]” or “greater thanabout [a value]” should be understood in view of the definition of theterm “about” provided herein. The terms “about” and “approximately” maybe used interchangeably. Throughout the present specification, numericalranges are provided for certain quantities.

As used herein, the verb “comprise” as used in this description and inthe claims and its conjugations are used in its non-limiting sense tomean that items following the word are included, but items notspecifically mentioned are not excluded.

As used herein, the word “comprising,” or variations such as “comprises”or “comprising,” will be understood to imply the inclusion of a statedelement, integer or step, or group of elements, integers or steps, butnot the exclusion of any other element, integer or step, or group ofelements, integers or steps. The present disclosure may suitably“comprise”, “consist of”, or “consist essentially of”, the steps,elements, and/or reagents described in the claims.

It is further noted that the claims may be drafted to exclude anyoptional element. As such, this statement is intended to serve asantecedent basis for use of such exclusive terminology as “solely”,“only” and the like in connection with the recitation of claim elements,or the use of a “negative” limitation.

As used herein, the term “percent weight” refers to the amount based onthe ophthalmic suspension, unless noted otherwise.

As used herein, the term “wax ester” refers to an ester of a fatty acidand a fatty alcohol. The wax esters provided herein may include longcarbon chains. The wax esters provided herein may be present in solidparticles that exhibit a melting point of from about 60° C. to about100° C. The wax esters provided herein may be natural beeswax. Naturalbeeswax is also commercially available as Cera Alba or Cera Flava (Whiteor Yellow Beeswax). The use of natural beeswax may include a hydrocarbonas a component. During the preparation of one embodiment of anophthalmic suspension of the present disclosure, the wax esters mayhydrolyze forming additional acids and/or alcohols as part of theprocess. The terms “wax ester dispersion” and “wax dispersion” may beused interchangeably.

As used herein, the term “particle size” refers to the size of wax esterparticles alone, or in combination with, one or more oil, phospholipid,surfactant, hyaluronic acid (HA), sodium hyaluronate, or any otherophthalmic suspension component provided herein.

As used herein, the term “dwell time” refers to the time (e.g., minutesor hours) that an ophthalmic suspension remains on the eye from oneapplication when evaluating the level or amount of lipid layer thicknessfrom a baseline on the eye. Lipid layer thickness can be determined byinterferometry instrumentation to measure dwell time on the eye.

As used herein, the term “long lasting” refers to the increase in thedwell time observed over a period of time and demonstrated compared toan untreated eye.

As used herein, the term “stable” refers to the time the tear filmmaintains structure between blinks.

As used herein, the term “tear film” refers to the entire protectivecoating provided to the eye as illustrated in FIG. 1 .

As used herein, the term “dry eye” refers to a condition of the eyewhere the tear film is unable to perform its function of lubrication andmay be caused by a lack of critical components to form a stable tearfilm.

As used herein, the terms “light mineral oil” and “light weight mineraloil” may be used interchangeably and refer to a low viscosity mineraloil as defined in the NF or USP formulary.

As used herein, the terms “heavy mineral oil” and “heavy weight mineraloil” may be used interchangeably and refer to a high viscosity mineraloil variant that meets the requirements of the NF or USP monographs formineral oil.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this disclosure belongs.

The present disclosure relates to ophthalmic suspensions and relatedmethods. The ophthalmic suspensions are particularly suited forincreasing the lipid layer thickness on the eye relative to a baselinelipid layer thickness. The ophthalmic suspensions provided herein forman artificial tear film over the ocular surface of the eye and provideenhanced ocular lubrication while reducing evaporation. The ophthalmicsuspensions remain on the eye and exhibit a dwell time substantiallylonger than any commercially available products currently on the market.The ophthalmic suspensions provided herein replicate not only thediscrete layers of the tear film, but also supplement interstitialbinding properties as well as build and thicken the tear film. As aresult, significant improvement in the duration of dry eye relief isprovided.

The ophthalmic suspensions provided include an aqueous phase and an oilphase. The aqueous phase may include water and one or more at least onewax ester, at least one anionic polar surfactant, at least one nonionicsurfactant, at least one salt and at least one phosphate. The waterutilized in the ophthalmic suspension vehicles provided herein may bepurified or deionized water. The oil phase may include at least onemineral oil and, optionally, at least one wax ester. Thus, the at leastone wax ester may be present in the aqueous phase, the oil phase, orboth the aqueous phase and oil phase. According to a particularembodiment, the at least one wax ester is in either the aqueous phase oroil phase.

The ophthalmic suspensions provided herein may be formulated as anoil-in-water emulsified suspension. An emulsified suspension, as theterm is used herein, is a suspension includes an aqueous and oil phasethat incorporate wax ester particulate components. The wax esterparticulates in the aqueous phase prefer to aggregate but are notsoluble in water. The lack of solubility is attributable to the waxester particles' significant charge stabilization. The wax esterparticulates in the oil phase do not appear to aggregate or mix withwater.

When an emulsified suspension is added to the eye as a standard drop,the emulsified suspension quickly differentiates permitting rapidformation of an oil film over the corneal surface without excessive oildischarge by blinking. The emulsified suspension may differentiatewithin about 10 blinks following application to the eye, more preferablyin a time of less than about 1 minute. During and followingdifferentiation of the emulsified suspension, the formation of the oilfilm is assisted by use of the surfactant combination which serves tohelp form the emulsified suspension and facilitate the spread of the oilover the surface of the eye as the emulsified suspension breaks.

In contrast to an emulsified ophthalmic suspension, a stable emulsionwill not differentiate rapidly when applied to the ocular surface. Anemulsion is typically optically opaque due to the presence of twodistinct phases. Therefore, an opaque emulsion over the surface of theeye is likely to cause blurring. The duration of blur is dependent uponthe time required for the emulsion to differentiate and form separatelayers replicating a tear film. In addition, the emulsion is most easilyadded to the eye as a standard drop from an eyedropper. The eye iscapable of holding a limited volume of fluid of volume that is less than25 μL. A volume of 25 μL is substantially less than the volume of astandard drop. Therefore, if the emulsion is stable and fails todifferentiate rapidly following application to the eye, excess emulsionwill be discharged from the eye during blinking. Discharge of theemulsion from the eye will result in discharge of efficacious componentsof the treatment suspension from the eye before a long-lasting tear filmcan be formed. For this reason, efficacious components may not beavailable in sufficient quantity to form the desired tear film.

The ophthalmic suspensions as provided herein are a free flowing liquidat room temperatures such as between about 20° C. to about 30° C. Theemulsified suspensions as provided herein separate into an oil phase anda water phase on contact with an eye. The surface of the eye typicallyexhibits a temperature of from about 32° C. to about 36° C.

According to a particular embodiment, the ophthalmic suspensionsprovided herein include an oil-in-water emulsion. The oil-in-wateremulsion includes at least one oil and water. The water may be purifiedor deionized water. The oil used to form an oil-in-water emulsion may bederived from animals, plants, nuts, or other suitable sources. The oilderived from animals, plant seeds, and nuts are similar to fats and areprimarily glycerides or fatty acids and consequently, contain asignificant number of acid and/or ester groups rendering the oil polar.Examples of these oils are safflower oil, corn oil, canola oil, whaleoil and seal oil or chemically similar oils. Additional oils that couldbe used to formulate an oil-in-water emulsion as provided herein includea vegetable oil such as a castor oil, almond oil, myrcia oil, corn oil,peanut oil, canola oil, safflower oil, kola nut oil, light olive oil,bay leaf oil, or other generally recognized as safe (GRAS) oils listedas being appropriate for ocular formulation. Alternatively, the oil maybe an oil suited for forming liposomes. According to one embodiment, theoil is a linear hydrocarbon oil having from 10 to 150 carbon atoms and,more preferably, the oil is a saturated n-alkane or isoalkanehydrocarbon having from 10 to 26 carbon atoms. Unsaturated alkenehydrocarbons may be used but are less chemically stable.

According to one embodiment, the oil as provided herein is a mineraloil. According to one embodiment, the oil as provided herein is alightweight mineral oil. According to one embodiment, the oil asprovided herein is a heavy weight mineral oil.

According to one embodiment, the oil includes a mixture of light weightmineral oil and heavy weight mineral oil each having differingviscosities. According to a particular embodiment, the light weightmineral oil exhibits a kinetic viscosity of from about 3.0 mm²s⁻¹ toabout 34.4 mm²s⁻¹ at 40° C. According to a particular embodiment, theheavy weight mineral oil exhibits a viscosity of kinetic viscosity offrom about 34.5 mm²s⁻¹ to about 150 mm²s⁻¹ at 40° C. According to yetanother embodiment, the light weight mineral oil exhibits a kineticviscosity of from about 28 mm²s⁻¹ to about 30 mm²s⁻¹ at 40° C. Accordingto yet another embodiment, the heavy weight mineral oil exhibits aviscosity of kinetic viscosity of from about 65 mm²s⁻¹ to about 71mm²s⁻¹ at 40° C.

The amount of oil within the oil-in-water emulsion may vary withinreasonable limits such that application to the eye does not exceed 25μL. According to one embodiment, the volume does not exceed 15 μL.According to one embodiment, the volume varies between about 1 μL and 10μL. According to one embodiment, the volume varies between about 1 μLand 30 μL.

The total amount of oil or combination of oils may be present in theophthalmic suspensions in an amount of at least about 0.1 percent byweight based on the total weight of the ophthalmic suspension. Accordingto one embodiment, the oil or combination of oils is present in anamount of at least about 0.5 percent by weight. According to oneembodiment, the oil or combination of oils is present in an amount of atleast about 1.0 percent by weight. According to one embodiment, the oilor combination of oils is present in an amount of at least about 1.5percent by weight. According to one embodiment, the oil or combinationof oils is present in an amount of less than about 12.5 percent byweight. According to one embodiment, the oil or combination of oils ispresent in an amount of less than about 10.0 percent by weight.According to one embodiment, the oil or combination of oils is presentin an amount of less than about 7.5 percent by weight. According to oneembodiment, the oil or combination of oils is present in an amount ofless than about 6.6 percent by weight. According to one embodiment, theoil or combination of oils is present in an amount of less than about6.5 percent by weight. According to one embodiment, the oil orcombination of oils is present in an amount of between about 0.5 percentby weight and about 12.5 percent by weight. According to one embodiment,the oil or combination of oils is present in an amount of between about1.0 percent by weight and about 8.5 percent by weight. According to oneembodiment, the oil or combination of oils is present in an amount ofbetween about 3.5 percent by weight and about 7.5 percent by weight.According to one embodiment, the oil or combination of oils is presentin an amount of between about 4.0 percent by weight and about 7.0percent by weight. According to one embodiment, the oil or combinationof oils is present in an amount of between about 4.4 percent by weightand about 6.6 percent by weight. According to one embodiment, the oil orcombination of oils is present in an amount of between about 4.95percent by weight and about 6.05 percent by weight.

According to one embodiment, the oil includes a mixture of two or moreoils of differing weight. According to such an embodiment, the oil is amixture of at least one light weight oil and at least one heavy weightoil. According to a particular embodiment, the oil is a mixture of themineral oils marketed under the tradenames Drakeol® 15 (light weightmineral oil) and Drakeol® 35 (white, heavy mineral oil). According toone embodiment, the lightweight mineral oil may be present in an amountof from about 0.5 percent by weight to about 1.5 percent by weight.According to one embodiment, the lightweight mineral oil may be presentin an amount of from about 0.6 percent by weight to about 1.4 percent byweight. According to one embodiment, the lightweight mineral oil may bepresent in an amount of from about 0.7 percent by weight to about 1.3percent by weight. According to one embodiment, the lightweight mineraloil may be present in an amount of from about 0.8 percent by weight toabout 1.2 percent by weight.

According to one embodiment, the heavy weight mineral oil may be presentin an amount of from about 2.7 percent by weight to about 6.5 percent byweight. According to one embodiment, the heavy weight mineral oil may bepresent in an amount of from about 2.9 percent by weight to about 6.3percent by weight. According to one embodiment, the heavy weight mineraloil may be present in an amount of from about 3.1 percent by weight toabout 6.1 percent by weight. According to one embodiment, the heavyweight mineral oil may be present in an amount of from about 3.3 percentby weight to about 5.9 percent by weight. According to one embodiment,the heavy weight mineral oil may be present in an amount of from about3.5 percent by weight to about 5.7 percent by weight. According to oneembodiment, the heavy weight mineral oil may be present in an amount offrom about 3.7 percent by weight to about 5.5 percent by weight.According to one embodiment, the heavy weight mineral oil may be presentin an amount of from about 4.05 percent by weight to about 4.95 percentby weight.

According to one embodiment, the light weight mineral oil may be presentin an amount of about 1.0 percent by weight and the heavy weight mineraloil may be present in an amount of about 4.5 percent by weight.

The ophthalmic suspensions provided herein include a wax esterdispersion. The wax dispersion includes at least one wax ester. Whilenot being bound to a particular theory, the role of wax esters and theirhydrolysis products is believed to maintain the integrity of theinterstitial layers themselves, binding the mucin layer to the aqueouslayer and aqueous layer to the lipid layer. In addition, the wax estersserve to build up an thicken the mucin, the aqueous layer, and the lipidlayer themselves. The binding process and subsequent homeostasis enabledby the wax esters allows the layers of the tear film to cling to eachother, thus allowing the entire tear film to remain on the eye forextended periods of time. The ophthalmic suspensions provided hereinpenetrate all layers of the tear film including the five interstitiallayers of which no product has incorporated previously.

According to one embodiment, the at least one wax ester is present in anamount of at least about 0.2 weight percent. According to oneembodiment, the at least one wax ester is present in an amount of atleast about 0.3 weight percent. According to one embodiment, the atleast one wax ester is present in an amount of at least about 0.4 weightpercent. According to one embodiment, the at least one wax ester ispresent in an amount of at least about 0.5 weight percent. According toone embodiment, the at least one wax ester is present in an amount of atleast about 0.6 weight percent. According to one embodiment, the atleast one wax ester is present in an amount of at least about 0.7 weightpercent. According to one embodiment, the at least one wax ester ispresent in an amount of at least about 0.8 weight percent. According toone embodiment, the at least one wax ester is present in an amount of atleast about 0.9 weight percent. According to one embodiment, the atleast one wax ester is present in an amount of at least about 1.0 weightpercent. According to one embodiment, the at least one wax ester ispresent in an amount of less than about 1.8 weight percent. According toone embodiment, the at least one wax ester is present in an amount offrom about 0.2 weight percent to about 1.8 weight percent. According toone embodiment, the at least one wax ester is present in an amount offrom about 0.4 weight percent to about 1.6 weight percent. According toone embodiment, the at least one wax ester is present in an amount offrom about 0.6 weight percent to about 1.4 weight percent. According toone embodiment, the at least one wax ester is present in an amount offrom about 0.8 weight percent to about 1.2 weight percent. According toone embodiment, the at least one wax ester is present in an amount ofabout 1.0 weight percent.

According to one embodiment, the at least one wax ester is a beeswax.According to one embodiment, the beeswax is a natural beeswax. Thebeeswax may be Cera Alba, Cera Flava, or a combination thereof. Thebeeswax may be USDA Certified Organic beeswax or conventional naturalbeeswax. According to one embodiment, at least one wax ester is asynthetic beeswax.

According to one embodiment, the wax ester particles may be emulsifiedinto the ophthalmic suspensions to form a range of specific particlesizes. The irregular shape and charge of the particles themselves allowthe wax ester particles more surface area to interact with the oil asprovided herein and allows the wax ester particles to break down at avaried rate, with the smaller wax ester particles and oil particlesbreaking down quickly, and the larger wax ester particles breaking downmore slowly. As wax ester particles are broken down, the oil and waxesters particles are believed to interact with the natural tear film tosupport a more stable barrier for the evaporation-prone aqueous tearfilm.

The ophthalmic suspensions provided herein include wax ester particlesthat exhibit a particle size with allow wax ester particles to beretained on the eye. According to one embodiment, the wax esterparticles exhibit a mean particle size of at least about 2.0 microns.According to one embodiment, the wax ester particles exhibit a meanparticle size of at least about 3.0 microns. According to oneembodiment, the wax ester particles exhibit a mean particle size of atleast about 4.0 microns. According to one embodiment, the wax esterparticles exhibit a mean particle size of at least about 5.0 microns.According to one embodiment, the wax ester particles exhibit a meanparticle size of less than about 30.0 microns. According to oneembodiment, the wax ester particles exhibit a mean particle size of lessthan about 25.0 microns. According to one embodiment, the wax esterparticles exhibit a mean particle size of less than about 24.0 microns.According to one embodiment, the wax ester particles exhibit a meanparticle size of less than about 23.0 microns. According to oneembodiment, the wax ester particles exhibit a mean particle size of lessthan about 22.0 microns. According to one embodiment, the wax esterparticles exhibit a mean particle size of less than about 21.0 microns.According to one embodiment, the wax ester particles exhibit a meanparticle size of less than about 20.0 microns. According to oneembodiment, the wax ester particles exhibit a mean particle size of atleast about 2.0 microns but less than about 25.0 microns. According toone embodiment, the wax ester particles exhibit a mean particle size ofat least about 2.0 microns but less than about 20.0 microns. Accordingto one embodiment, the wax ester particles exhibit a mean particle sizeof at least about 2.0 microns but less than about 15.0 microns.According to one embodiment, the wax ester particles exhibit a meanparticle size of at least about 3.0 microns but less than about 24.0microns. According to one embodiment, the wax ester particles exhibit amean particle size of at least about 4.0 microns but less than about23.0 microns. According to one embodiment, the wax ester particlesexhibit a mean particle size of at least about 5.0 microns but less thanabout 22.0 microns. According to one embodiment, the wax ester particlesexhibit a mean particle size of at least about 6.0 microns but less thanabout 21.0 microns. According to one embodiment, the wax ester particlesexhibit a mean particle size of at least about 7.0 microns but less thanabout 20.0 microns.

The wax ester dispersion includes at least one surfactant. According toone embodiment, the wax dispersion includes two or more surfactants.According to one embodiment, the wax dispersion includes a combinationof surfactants for the dual purpose of stabilizing the suspension aswell as spreading and maintaining the suspension over the ocular surfacefollowing application to the eye. The surfactant combination may includea primary surfactant and secondary surfactant. The at least onesurfactant enables formation of a suspension that is stable inmanufacture and during storage, but desirably meta stable when appliedto the ocular surface. The at least one surfactant as provided herein issuitable for rapidly differentiation when applied to the eye whereby anon-blurring film of oil is rapidly formed over the ocular surface anddisseminates the wax ester through each phase of the emulsifiedsuspension.

According to one embodiment, the at least one surfactant includes atleast one polyoxyethylene sorbitan monooleate such aspolyoxyethylene-sorbitan-20 mono-oleate which is commercially availableas Polysorbate 80 or Tween 80. According to one embodiment, thepolyoxyethylene sorbitan monooleate may be present in the ophthalmicsuspension in an amount of from about 0.1 percent weight to about 0.7percent weight. According to one embodiment, the polyoxyethylenesorbitan monooleate may be present in the ophthalmic suspension in anamount of from about 0.2 percent weight to about 0.6 percent weight.According to one embodiment, the polyoxyethylene sorbitan monooleate maybe present in the ophthalmic suspension in an amount of from about 0.3percent weight to about 0.6 percent weight. According to one embodiment,the polyoxyethylene sorbitan monooleate may be present in the ophthalmicsuspension in an amount of from about 0.4 percent weight to about 0.6percent weight.

According to one embodiment, the at least one surfactant includesdiphosphatidylglycerol such as dimyristoylphosphatidylglycerol or1,2-Dimyristoyl-sn-glycero-3-phosphorylglycerol sodium salt (DMPG) whichis commercially available. The]surfactant may be alysophosphatidylcholine, a phosphatidic acid, a phosphatidylcholine, aphosphatidylethanolamine, a phosphatidylglycerol, or aphosphatidylserine. In other embodiments, the surfactant includes atleast one anionic surfactant. According to one embodiment, the anionicsurfactant may be one or more of an anionic polar phospholipid, such asa lysophosphatidylcholine, a phosphatidic acid, a phosphatidylcholine, aphosphatidylethanolamine, a phosphatidylglycerol, or aphosphatidylserine. According to another embodiment, the anionic polarphospholipid may be one or more of phosphatidic acid (PA),phosphatidylserine (PS), phosphatidylinositol (PI), and itsphosphorylated derivatives the phosphoinositides (e.g.phosphatidylinositol-4-phosphate [PI4P] andphosphatidylinositol-4,5-bisphosphate, also dimyristoylphopatidylglycerol. According to one embodiment, the anionic surfactant is adimyristoylphosphatidylglycerol. According to one embodiment, thesurfactant is a mixture of two surfactants as provided herein. Accordingto one embodiment, the surfactant is a combination of two anionic polarphospholipids. According to one embodiment, the anionic polar surfactantis a mixture of a Tween 80 and anionic polardimyristoylphosphatidylglycerol.

According to one embodiment, the dimyristoylphosphatidylglycerol may bepresent in the ophthalmic suspension in an amount of from about 0.1percent weight to about 0.7 percent weight. According to one embodiment,the dimyristoylphosphatidylglycerol may be present in the ophthalmicsuspension in an amount of from about 0.2 percent weight to about 0.6percent weight. According to one embodiment, thedimyristoylphosphatidylglycerol may be present in the ophthalmicsuspension in an amount of from about 0.3 percent weight to about 0.6percent weight. According to one embodiment, thedimyristoylphosphatidylglycerol may be present in the ophthalmicsuspension in an amount of from about 0.4 percent weight to about 0.6percent weight.

According to one embodiment, the ophthalmic suspensions provided hereininclude one or more phosphates. According to one embodiment, theophthalmic suspensions include both a monobasic and a dibasic phosphate.

According to a particular embodiment, the monobasic phosphate ismonosodium phosphate (monobasic sodium phosphate) such as NaH₂PO₄.According to one embodiment, the monobasic phosphate may be present inan amount of from about 0.01 percent by weight to about 0.05 percent byweight. According to one embodiment, the monobasic phosphate may bepresent in an amount of from about 0.02 percent by weight to about 0.04percent by weight. According to one embodiment, the monobasic phosphatemay be present in an amount of about 0.03 percent by weight.

According to a particular embodiment, the dibasic phosphate is disodiumphosphate (sodium hydrogen phosphate or sodium phosphate dibasic) suchas Na₂HPO₄. According to one embodiment, the dibasic phosphate may bepresent in an amount of from about 0.1 percent by weight to about 0.5percent by weight. According to one embodiment, the dibasic phosphatemay be present in an amount of from about 0.2 percent by weight to about0.3 percent by weight. According to one embodiment, the dibasicphosphate may be present in an amount of about 0.25 percent by weight.

According to one embodiment, the ophthalmic suspensions provided hereininclude at least one salt. According to one embodiment, the at least onesalt is sodium chloride or other suitable salt for ophthalmicapplication. The at least one salt may be present in an amount of fromabout 0.50 percent weight to about 0.75 percent weight. According toanother embodiment, the at least one salt may be present in an amount offrom about 0.55 percent weight to about 0.70 percent weight. Accordingto another embodiment, the at least one salt may be present in an amountof about 0.55 percent weight. According to another embodiment, the atleast one salt may be present in an amount of about 0.67 percent weight.

According to one embodiment, the ophthalmic suspensions provided hereininclude at least one glycosylaminoglycan. A suitable glycosylaminoglycanincludes hyaluronic acid (HA), the corresponding sodium salt, sodiumhyaluronate, or a combination thereof. According to one embodiment, thehyaluronic acid or sodium hyaluronate may be present in the ophthalmicsuspensions in an amount of from about 0.06 percent about to about 0.5percent weight. According to one embodiment, the hyaluronic acid orsodium hyaluronate may be present in the ophthalmic suspensions in anamount of from about 0.07 percent about to about 0.4 percent weight.According to one embodiment, the hyaluronic acid or sodium hyaluronatemay be present in the ophthalmic suspensions in an amount of from about0.08 percent about to about 0.3 percent weight. According to oneembodiment, the hyaluronic acid or sodium hyaluronate may be present inthe ophthalmic suspensions in an amount of from about 0.09 percent aboutto about 0.2 percent weight. According to one embodiment, the hyaluronicacid or sodium hyaluronate may be present in the ophthalmic suspensionsin an amount of about 0.1 percent weight.

According to one embodiment, the ophthalmic suspensions provided hereinoptionally include ethylenediaminetetraacetic acid (EDTA). According toone embodiment, the EDTA may be present in the ophthalmic suspension inan amount of from about 0.007 percent weight to about 0.02 percentweight. According to one embodiment, the EDTA may be present in theophthalmic suspension in an amount of from about 0.008 percent weight toabout 0.015 percent weight. According to one embodiment, the EDTA may bepresent in the ophthalmic suspension in an amount of about 0.01 percentweight.

According to one embodiment, the ophthalmic suspensions provided hereinoptionally include at least one anti-inflammatory compound such asdeactivated brewer's yeast or adenosine diphosphate ribose. Whenpresent, the at least one anti-inflammatory compound does not impactophthalmic suspension stability or on-eye performance. According to oneembodiment, the anti-inflammatory compound may be present in theophthalmic suspension in an amount of from about 0.02 percent weight toabout 1.0 percent weight.

Other additives may be present in the ophthalmic suspension. Suchadditives include minor amounts of neutral lipids and oils such as oneor more triglycerides, partially hydroylyzed esters, cholesterol esters,high molecular weight isoprenoids; stabilizers, additional surfactants;mucomimetics (e.g., HP Guar); preservatives; pH adjusters; salt, buffer,glycerol, a sugar in sufficient concentration to form a mildly hypotoniccomposition such that the emulsion is not stable in the ocularenvironment; emollients; demulcents; polymers of ethylene oxide,propylene oxide, or butylene oxide; carboxymethylcellulose (CMC);hydroxypropyl methylcellulose (HPMC); polyacrylic acid (PAA);polyethylene glycol; (PEG) propylene glycol (PG); or polyvinyl alcohol(PVA).

The ophthalmic suspensions provided herein have an osmolality that canbe adjusted by the concentration of salts such as NaCl. According to oneembodiment, the ophthalmic suspensions provided herein have anosmolality of at least about 245 mOsmol/kg. According to one embodiment,the ophthalmic suspensions provided herein have an osmolality of atleast about 260 mOsmol/kg. According to one embodiment, the ophthalmicsuspensions provided herein have an osmolality of from about 245mOsmol/kg to about 315 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about245 mOsmol/kg to about 310 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about255 mOsmol/kg to about 305 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about270 mOsmol/kg to about 300 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about275 mOsmol/kg to about 295 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about280 mOsmol/kg to about 290 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about282 mOsmol/kg to about 289 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of from about285 mOsmol/kg to about 287 mOsmol/kg. According to one embodiment, theophthalmic suspensions provided herein have an osmolality of about 286mOsmol/kg.

According to one embodiment, the ophthalmic suspensions provided hereinhave a pH of between about 6.8 and 7.8. According to one embodiment, theophthalmic suspensions provided herein have a pH of between about 6.9and 7.7. According to one embodiment, the ophthalmic suspensionsprovided herein have a pH of between about 7.0 and 7.6. According to oneembodiment, the ophthalmic suspensions provided herein have a pH ofbetween about 7.0 and 7.4. According to one embodiment, the ophthalmicsuspensions provided herein have a pH of between about 7.1 and 7.5.According to one embodiment, the ophthalmic suspensions provided hereinhave a pH of between about 7.2 and 7.4. According to one embodiment, theophthalmic suspensions provided herein have a pH of about 7.2. Accordingto one embodiment, the ophthalmic suspensions provided herein have a pHof about 7.3. The pH may be adjusted by addition of pH adjusters such asHCl or citric acid or a base such as NaOH.

The viscosity of the ophthalmic suspensions described herein may varybut will exhibit a viscosity allows appropriate drop size forapplication to the eye. According to one embodiment, the viscosity ofthe ophthalmic suspensions provided herein exhibit a viscosity of fromabout 5 centipoise at 25° C. to about 8 centipoise at 25° C. Theviscosity of the ophthalmic suspensions described herein may be measuredusing techniques well-known to those skilled in the art. Non-limitingexamples of methods to measure viscosity include falling ballviscometers, viscosity cups, consistometers (measuring flow on anincline), capillary glass viscometers, or rotational viscometers. Avariety of instruments are commercially available (Cole-PalmerInstrument Co., Vernon Hills, IL, USA).

The ophthalmic suspensions provided herein are preservative-free. Insome embodiments, preservative-free ophthalmic suspensions are deliveredin single use packages because of the risk of bacterial contaminationassociated with conventional multi-use applications. In anotherembodiment, the ophthalmic suspension is delivered in a sterilemultidose bottle. Examples include the Aptar Pharma (Crystal Lake, IL,USA) multidose squeeze dispenser which operates mechanically andutilizes a filter membrane (see PCT Publication Nos. WO 2017/074420 andWO 2017/132190 (Aptargroup, Inc.); Nemera La Verpillier (France)multidose squeeze bottle (see PCT Publication WO2013/140069)).

According to an alternative embodiment, the ophthalmic suspensionsprovided herein may include at least one preservative. According to analternative embodiment, the ophthalmic suspensions provided herein mayinclude at least one borate buffer.

Methods of preparing ophthalmic suspension vehicles are provided.According to one embodiment, the method of preparation of the ophthalmicsuspension vehicle includes the step of separately preparing a mixtureof the oils (e.g., heavy weight mineral oil and light weight mineraloil) and adding the wax ester component, such as beeswax, and heatingthe mixture to a temperature above the melting point of the wax ester(e.g., from about 63° C. to about 71° C.). In a separate water/aqueousphase, the salts, phosphates, surfactants and any other water-solubleingredient may be prepared and heated to approximately 85° C. The oilphase may then be slowly added to the water/aqueous phase, mixed, andhomogenized to form the ophthalmic suspension vehicle. The resultingophthalmic suspension vehicle is autoclaved. Throughout the process, theophthalmic suspension vehicle continues to be mixed.

According to one embodiment, the method of preparation of the ophthalmicsuspension vehicle includes the step of separately preparing the oilphase (e.g., heavy weight mineral oil and light weight mineral oil)heating to a temperature of from about 63° C. to about 71° C. The stepof preparing the oil phase may optionally include the step of adding orintroducing at least one wax ester to the oil phase followed by heatingthe mixture to a temperature above the melting point of the wax ester(e.g., from about 63° C. to about 71° C.).

According to one embodiment, the method of preparation of the ophthalmicsuspension vehicle includes the step of separately preparing the aqueousphase. The aqueous phase may be prepared by mixing the at least one waxester, at least one salt, at least one phosphate, at least onesurfactant and any other water-soluble ingredient followed by heatingthe mixture to a temperature above the melting point of the wax ester(e.g., from about 63° C. to about 71° C.).

According to one embodiment, the oil phase as provided herein may thenslowly added to the aqueous phase, mixed, and homogenized to form theophthalmic suspension vehicle. The resulting ophthalmic suspensionvehicle may then be autoclaved. Thus, according to such an embodiment,the individual oil phase and aqueous phase are not separately autoclavedprior to being combined. According to one embodiment, the resultingophthalmic suspension vehicle is not autoclaved and sterilized accordingto an alternative method such as, for example, e-beam or gammairradiation, or filtration.

According to an alternative embodiment, a method of preparing anophthalmic suspension vehicle is provided. This alternative methodincludes the step of preparing a wax dispersion by mixing or dissolvingat least one wax ester (such as a natural beeswax) with a surfactant andpurified or deionized water. According to one embodiment, the at leastone wax ester may be mixed or dissolved in such a way that the naturalwax esters can be delivered in a controlled manner leading to increaseddwell time on the eye. According to one embodiment, the step ofpreparing a wax dispersion includes dissolving one or more salts and oneor more phosphates such as a monosodium phosphate and disodium phosphatein the purified or deionized water. According to one embodiment, thestep of preparing a wax dispersion includes heating the one or moresalts, phosphates, surfactants and wax esters and stirring the resultingdispersion. According to one embodiment, the dispersion is heated toabout 70° C. to about 90° C. According to a particular embodiment, waxparticle dispersions may be prepared by homogenization of melted beeswax(˜1.0%) in purified or distilled water containing salts, phosphates withadded Octoxynol-40 (˜0.2%1,2-Dimyristoyl-sn-glycero-3-phosphorylglycerol sodium salt (DMPG)) atabout 75° C. The high cloud point of Octoxynol-40 (>100° C.) allowsemulsifying efficiency at higher temperatures by a decrease in its watersolubility (effective lowering of the HLB value).

The alternative method includes the step of preparing an oil-in-wateremulsion. According to one embodiment, the step of preparing anoil-in-water emulsion includes mixing differing weight or viscosity ofmineral oils as described herein and heating the mixture of mineral oilsto a temperature of from about 65° C. to about 75° C. According to oneembodiment, the step of preparing an oil-in-water emulsion includesdropwise introducing the mixture of heated mineral oils to purified ordeionized water and homogenizing the water and mineral oil mixture toform an oil-in-water emulsion. The pH of the oil-in-water emulsion maybe adjusted to a range of from about 6.8 to about 7.8.

The alternative method includes the step of separately autoclaving thewax dispersion and the oil-in-water emulsion. The integrity of theemulsion is maintained during autoclaving.

While not being bound to a particular theory, the mechanism involved inthe irreversible aggregation of the wax (wax breakout) under autoclaveconditions is believed to involve the presence of relatively high(approximately isotonic) salt concentrations. This high ionic loading isbelieved to significantly decrease the zeta-potential of the wax esterparticles, which removes an important stabilization mechanism when thesedispersions are subjected to autoclave conditions.

The alternative method includes the step of aseptically blending theautoclaved beeswax dispersion and the oil-in-water emulsion so as toprepare the ophthalmic suspension vehicles as provided herein. Accordingto one embodiment, the wax ester particles may be stabilized by thesurfactant in the oil phase preventing flocculation and dropletaggregations during cooling.

To maintain a shelf stable suspension, separate preparation andautoclaving of the wax ester particle dispersion and emulsion componentsis performed, followed by an aseptic blending step to ensure productsterility. The aseptic blending step of the autoclaved beeswaxdispersion and the oil-in-water emulsion ensures that the desired finalconcentrations of mineral oil, beeswax, and other components are presentin the ophthalmic suspension. According to one embodiment, theoil-in-water emulsion is formulated with increased component levels,while the beeswax particles are emulsified in water with an addedsurfactant. The concentrations of the various components in the twofractions (before autoclaving) can be tailored to permit a relativelywide variation of final emulsified suspension compositions.

According to one embodiment, the method of preparation includes the stepof separately preparing a mixture of the oils (e.g., heavy weightmineral oil and light weight mineral oil) and adding the wax estercomponent such as beeswax and heating the mixture to a temperature abovethe melting point of the wax ester (e.g., 63° C. to 71° C.). In aseparate phase, the salts, phosphates, surfactants and any otherwater-soluble ingredient are prepared and heated to approximately 85° C.The oil phase is slowly added to the water phase, mixed, andhomogenized. The resulting preparation is autoclaved. Throughout theprocess, the preparation continues to be mixed.

According to one embodiment, the method of preparation includes the stepof mixing an oil phase containing light mineral, mineral oil and waxester (e.g., natural or synthetic bees wax) with an aqueous phasecontaining a salt, phosphate, surfactant and a water solubleglycosaminoglycan followed by homogenizing and autoclaving to form acomplex combination of particles. Larger particles are observed in theresulting preparation that are about 2 microns to about 15 micronsaccording to particle analysis via Microtrac particle size analysis.According to one embodiment, measurement of particles for zeta potentialor surface charge demonstrate zeta potential of greater than −60 mV.According to one embodiment, measurement of particles for zeta potentialor surface charge demonstrates zeta potential of from about −60 mV toabout −110 mV. Within the preparation, there are both charged particlesresulting from interaction with the surfactant that may found in thewater phase and particles found in the oil phase which are submicron insize. The particles in the oil phase may be wax-ester particles, or oilwax-ester mixtures that may either have neutral charge or surfacecharge.

Large sized particle dispersions cannot be prepared in the absence ofadded surfactant. The operating particle formation mechanism isdifferent from a simple nucleation and particle growth model used in theformation of submicron sized dispersions. The added surfactantstabilizes the growing beeswax droplets during homogenization. Thesurfactant prevents droplet aggregation during the cooling period afterautoclaving. The chemistry of the system yields particle dispersionsthat are stable in the autoclave (as melted wax droplets), but whichaggregate irreversibly once the decreasing sample temperature duringsample cooling approaches the melting point (crystallizationtemperature) of the beeswax. Specifically, the presence of surfactantsuch as DMPG is also believed to aid in stabilizing the beeswaxemulsions at the high temperatures present in the autoclave.Particularly, the surfactant is believed to stabilize the melted waxdroplets by re-partitioning from the dissolved state in the aqueousphase onto the particle/droplet surfaces and preventing flocculation. Astemperature continuously increases during the autoclaving process, thesurfactant becomes increasingly insoluble in water, and tends to migratetowards the particle surface (droplet/aqueous interface) helping tostabilize the melted wax droplet.

Although the zeta potential values cannot be measured under autoclaveconditions, sealed beeswax particles/droplets dispersions remain stableat 121° C. (with gentle stirring) when dispersed in water. Further, theoil-in-water emulsions provided herein are not subjected to significantamounts of particle aggregation when prepared according to the presentmethods. Strong long-term stability characteristics are believed to bethe result of such methods.

EXAMPLES Ophthalmic Suspension Preparation

The ophthalmic suspension utilized in the Examples provided herein isset forth in Table 1, below.

TABLE 1 Component Weight % Water 90.00-95.00 NaCl 0.10-0.90 NaH₂PO₄0.01-0.05 Na₂HPO₄ 0.10-0.50 Tween-80 0.10-0.70 DMPG 0.35-0.55 Wax ester0.80-1.20 Sodium 0.06-0.50 Hyaluronate Drakeol ® - 35 2.7-6.5Drakeol ® - 15 0.50-1.50

To prepare a 500 gram batch of the ophthalmic suspension, NaCl,dimyristoylphosphatidylglycerol (DPMG), NaH₂PO₄ and Na₂HPO₄ weredissolved in purified water in a beaker. Tween 80, DPMG, and sodiumhyaluronate were added to the aqueous solution and heated withcontinuous stirring to 85° C. (+/−2° C.). In a separate glass beaker,Drakeol® 15, Drakeol® 35 and wax ester were mixed and heated to 71° C.(+/−2° C.) with continuous stirring for 10 minutes (+/−20 seconds). Theaqueous phase was homogenized for 30 seconds (+/−5 seconds). The oilphase was pre-heated to 71° C. (+/−2° C.) and added dropwise to theaqueous phase at 85° C. (+/−2° C.), while the homogenizer was running.After the addition of the oil was complete, the homogenizer was run. Thetarget homogenization speed was around 10,000 RPM (+/−400 RPM) and thetarget homogenization time was about 4 min (+/−20 seconds). Thehomogenization procedure was terminated and stirring continued until thesuspension reached room temperature (approximately 4 hours). Whilestirring, the pH and osmolality were checked and adjusted (target pH:7.2-7.4: osmolality of 240 mOsmol/kg-290 mOsmol/kg). While stirring, thesuspension mixture was dispensed using a syringe to an autoclavablebottle and charged with a magnetic stir bar. The bottle and autoclavewere closed for 35 minutes (+/−1 minute) and heated to/at 121° C. and 15psi while stirring. The suspension was allowed to cool to roomtemperature while stirring (approximately 6 hours).

Example 1 Wax Ester Impact on Ocular Emulsion Retention

Testing was conducted to determine wax ester impact on lipid layerthickness. At instillation of a single drop, blurring and comfort scoreswere noted and interferometric measurements of lipid layer thicknesswere then taken from both eyes at 5, 30, 60, and 120-minute intervals.The improvement of lipid layer thickness over baseline was calculatedand subtracted (or added) the net result of the control drop at eachtime interval. The results for the ophthalmic solution of Table 1 isillustrated in Table 2. Ophthalmic solutions that contain no wax ester(commercially available as Soothe® XP) and two additional commerciallyavailable solutions—Refresh Optive® Advanced and Systane® Balance—weretested with results shown in Table 2, 3, 4 and 5, respectively, below.

TABLE 2 Ophthalmic Suspension Increase in LLT Over Time BaselineRelative to Interval Control (nm)  5 Minutes 29  30 Minutes 31  60Minutes 29 120 Minutes 25

TABLE 3 Refresh Optive ® Advanced Increase in LLT Over Time BaselineRelative to Interval Control (nm)  5 Minutes 2  30 Minutes 7  60 Minutes−2 120 Minutes 1

TABLE 4 Soothe ® XP (no wax) Increase in LLT Over Time Baseline Relativeto Interval Control (nm)  5 Minutes 13  30 Minutes 1  60 Minutes −2 120Minutes −4

TABLE 5 Systane ® Balance Increase in LLT Over Time Baseline Relative toInterval Control (nm)  5 Minutes 2  30 Minutes 4  60 Minutes 8 120Minutes 1

Testing determined that mineral oil alone added to the ocularenvironment is rapidly lost, most likely through the regular exchange ofthe tear film or by ocular drainage from the tear glands. The additionof the wax ester was shown to provide an ophthalmic suspension that isretained for an extended period in the ocular environment allowing theophthalmic suspension to continue to augment an increase the lipidlayer.

Example 2 Wax and Surfactant Selection

The inclusion of different wax esters provides an indication of the keyattributes required to maintain the effects of the addition of waxesters to the ocular environment. In order to understand the roledemonstrating enhanced enhancement of the lipid layer, the role of thewax ester ingredient and the use of surfactant ingredients wasevaluated. The following wax esters were evaluated: Wax ester, KesterK-24, Branched Kester BK-40, and Synthetic Wax ester.

One or more of the following surfactants were utilized with the notedwax esters: DMPG DimyristoylphosphatidylGlycerol (an anionicphospholipid); IGEPAL CA 897 Ethoxylated(40)-1,1,3,3 Tetramethylbutylphenol; Phospholipon 90G phosphatidylcholine (zwitterionic chargedphospholipid); and IGEPAL CO-890 Polyoxyethylene (40) nonylphenyl ether,branched. The results are summarized in Tables 6-10, below.

TABLE 6 Beeswax Time Increase in LLT Over Baseline Relative to Control(nm) Interval 90G CA897 CO-890 DMPG  5 Minutes 14 20  7 29  30 Minutes20 24 24 31  60 Minutes 17 19 23 29 120 Minutes 15 18 16 25

TABLE 7 BK Kester Time Increase in LLT Over Baseline Relative to Control(nm) Interval 90G CA897 DMPG  5 Minutes 10 3  0  30 Minutes  4 1  6  60Minutes −1 0  7 120 Minutes n/a 5 14

TABLE 8 BK Kester/Kester K24 Time Increase in LLT Over Baseline Relativeto Control (nm) Interval 90G CA897 DMPG  5 Minutes  5  3 −24  30 Minutes−11 24  2  60 Minutes −17  4  −2 120 Minutes n/a n/a n/a

TABLE 9 Kester K24 Time Increase in LLT Over Baseline Relative toControl (nm) Interval 90G CA897 DMPG  5 Minutes  2  1 4  30 Minutes 28 1 2  60 Minutes  5 −4 3 120 Minutes −1 n/a n/a

TABLE 10 Synthetic Beeswax Time Increase in LLT Over Baseline Relativeto Control (nm) Interval 90G CA897 DMPG  5 Minutes 20 24 22  30 Minutes27 26 20  60 Minutes 20 18 10 120 Minutes 13 11  8

The preceding results illustrate that lower melting point wax esters hadno significant on-eye effect relative to the control product and weresimilar to the commercially available product. The natural beeswax waxester and the synthetic beeswax wax ester saw improved results with allsurfactant combinations with the natural beeswax wax ester demonstratingthe best results overall.

Example 3 Wax and Surfactant Combination Selection

Natural and synthetic beeswax wax esters were tested to identify whichsurfactant allowed for quick lipid layer improvement and extendedresidence time on the eye (in addition to in-bottle stability). One ormore of the following surfactants were utilized with the noted waxesters: DMPG dimyristoylphosphatidylglycerol (an anionic phospholipid);IGAPEL CA 897 Ethoxylated(40)-1,1,3,3 Tetramethylbutyl phenol;Phospholipon 90G phosphatidylcholine (zwitterionic chargedphospholipid); and IGEPAL CO-890 Polyoxyethylene (40) nonylphenyl ether,branched. The results for natural beeswax are summarized in Table 11,below. The results for synthetic beeswax are summarized in Table 12,below.

TABLE 11 Natural Beeswax Average Average Average Average IncreaseIncrease Increase Increase (nm) Over (nm) Over (nm) Over (nm) OverBaseline Baseline Baseline Baseline Relative to Relative to Relative toRelative to Control: Control: Control: Control: Surfactant 5 Minutes 30Minutes 60 Minutes 120 Minutes n 90G 13.55 19.64 17.14 14.57 22 CA 89720.46 24.00 19.35 18.03 37 CO-890 7.00 23.80 23.00 16.20 5 DMPG 28.9331.31 28.75 25.43 79

TABLE 12 Synthetic Beeswax Average Average Average Average IncreaseIncrease Increase Increase (nm) Over (nm) Over (nm) Over (nm) OverBaseline Baseline Baseline Baseline Relative to Relative to Relative toRelative to Control: Control: Control: Control: Surfactant 5 Minutes 30Minutes 60 Minutes 120 Minutes n 90G 20.27 27.20 19.60 13.47 15 CA 89723.50 26.00 17.50 11.00 4 DMPG 21.93 20.40 9.73 8.20 5

The natural beeswax wax ester and the anionic surfactant DMPG was shownto provide superior results across all time intervals. The naturalbeeswaxes, in general, were shown to attain and maintain higher averageincrease in lipid layer thickness after 120 minutes.

Example 4 Particle Size

In order to provide the desired characteristics, the oil and wax esterportion of the ophthalmic suspension should be retained in the ocularenvironment for an extended period of time. Wax ester particle size ispreferably maintained to provide for long lasting lipid layer increaseson eye over time.

Particle size was determined utilizing a Microtrac Sync 3R Flow device.Particle size analysis was carried out using samples of about 6.0 mLthat may be stored in plastic bottles until testing. Prior to testing,each bottle was shaken 10 times. The entire cap was then removed andapproximately two drops of sample were transferred to the Microtrac Sync3R Flow device using a plastic pipette. The sample was loaded to theparticle size analyzer. Approximately two drops (0.060 g) of sample wereinjected into a 200 mL deionized water circulating chamber and testingwas initiated.

Results from mineral oil alone indicated that the loss of added mineraloil does not extend beyond 30 minutes as observed in the competitiveproduct, Systane® Balance. The results are summarized in Table 13.

The processing parameter labeled “Homogenizer” in Table 13 refers toprocessing by only the homogenizer in the range of from about 10k toabout 18k rpm for about 4 to about 8 minutes. The other processingparameters refer to the pressure of the micofluidizer system utilized toevaluate homogeneity. This additional processing was added after initialhomogenization and resulted in a reduction in particle size butdecreased the clinical performance (average increase in over baseline).More specifically, based on particle size analysis conducted on severaltest formulas, the homogenizer-only process yielded mean particle sizesin the 2 to 20 micron range while samples further processed with amicrofluidizer yields mean particle sizes of micron. Actual measurementsof the formulations determined the significant range for particle sizeand distribution. Specifically, formulations with mean particle sizes ofabout ≤1 micron do not remain in the eye, while the best-performingformulas had a mean particle size in the 5 to 20 micron range under theconditions of the measurement.

TABLE 13 Average Average Average Average Increase Increase IncreaseIncrease (nm) Over (nm) Over (nm) Over (nm) Over Average BaselineBaseline Baseline Baseline of Mean Relative Relative Relative RelativeProcessing Particle to Control: to Control: to Control: to Control:Parameter Size 5 30 60 120 (kpsi) (nm) Minutes Minutes Minutes Minutes NHomo- 13.6 19.2 22.1 20.7 17.4 32 genizer 2.5  4.7  7.9 14.4 12.5 13.1 8 5  8.9 13.8 16.0 21.0  8.3  6 10  2.3  2.1 21.6 14.9  6.7  7 15  1.7−1.3  3.5 22.3  6.8  6 20  0.9  0.3  4.4  4.8  6.8 10

Example 5 Ophthalmic Suspension On-Eye Performance

A study was conducted to evaluate the on-eye performance of theophthalmic suspension as set forth in Table 1. The study yieldedpositive results both in terms of emulsified suspension properties andon-eye performance. Particularly, studies were conducted on patients whoexhibited diminished tear film with low levels of lipid layer thickness(LLT) based on previous and day-of screenings. The thickness of thelipid layer of the tear film at baseline using interferometry wasmeasured. The baseline lipid layer thickness for these patients rangedfrom 25 nm to 70 nm with an average of 45 nm. A lipid layer thickness ofless than 70 nm was considered deficient.

After the baseline measurements were taken, a single test drop of theophthalmic suspension in Table 1 (of Example 1) and a single controldrop were self-instilled in contralateral eyes. The control dropselected was the solution commercially available as Systane® Ultra PF(commercially available, a non-lipid containing drop that is free ofpreservatives).

With the main objective being an evaluation of increase of lipid layerthickness, the first challenge was to develop a rigorous inclusion andexclusion criteria for patient recruitment to select subjects that had achronically desiccated tear film due to Evaporative Dry Eye (e.g.,Meibomian Gland Dysfunction or MGD), rather than partial blinking or aside effect of another medication or procedure. Primarily, this studysought subjects with a baseline lipid layer thickness of less than 55 nmin at least one eye, and less than 50% partial blinking rate, bothmeasured using the LipiView (Johnson and Johnson). Additionally,patients with elevated risk factors such as other ocular diseases,pregnancy, or recent use of certain drugs were not considered for thisevaluation.

Once inclusion criteria were established, a formal protocol for theclinician and staff to follow had to be created. In this document, eachstep of the patient evaluation process was laid out in a checkboxformat; from initial patient evaluation and day-of confirmation ofinclusion to the actual evaluation and measurement processes. Each stepwas documented for the physician and staff to follow sequentially:

-   -   1. Inclusion determination    -   2. Exclusion confirmation    -   3. Ocular health exam (Evaluation specifics were at the        physician's discretion)    -   4. Baseline LLT reading    -   5. SPEED Pre-assessment        -   (Standard Patient Evaluation of Eye Dryness), see Korb et            al. Lid wiper epitheliopathy and dry eye symptoms. Eye            Contact Lens. 2005 January; 31(1):2-8; and Korb et al. The            effect of two novel lubricant eye drops on tear film lipid            layer thickness in subjects with dry eye symptoms. Optom Vis            Sci. 2005 July; 82(7):594-601, each incorporated by            reference with regard to such survey testing.    -   6. Test and Control Drop Instillation    -   7. Measurement at 5, 30, 60, 120, 180, and 240-minute time        intervals    -   8. SPEED Post-Assessment

The drops were masked to the patients, but not masked for the physicianand staff. All study results were recorded on a data record form withpatient identity masked.

Over the course of two weeks, 12 patients completed the study. Theresults, as illustrated in Tables 14 and 15, show the raw average lipidlayer thickness readings for the 12 patients measured. The ophthalmicsuspension of Table 1 showed a significant increase in lipid layerthickness at the 5 and 30-minute time points. At all-time points, therewas significant separation between the ophthalmic suspension and thecontrol drop. The ophthalmic suspension maintained a 72.5 (+/−3.8) nmaverage lipid layer thickness at the 4-hour mark compared with thecontrol at 61.8 (+/−2.2) nm.

TABLE 14 Ophthalmic Suspension Time Lipid Layer Interval Thickness (nm)Baseline 49.5  5 Minutes 79.2  30 Minutes 77.6  60 Minutes 70.2 120Minutes 74.0 180 Minutes 70.4 240 Minutes 72.5

TABLE 15 Systane ® Ultra Time Lipid Layer Interval Thickness (nm)Baseline 57.6  5 Minutes 66.8  30 Minutes 66.2  60 Minutes 61.3 120Minutes 61.1 180 Minutes 63.5 240 Minutes 61.2

Based on the raw data from contralateral eyes, differences emerged inthe average baseline lipid layer thickness in the test and control eyes.Thus, in addition to using lipid layer thickness at each time point as akey metric, the average increase from baseline in lipid layer thicknessacross patients with both the test and control drops was evaluated.Table 16 provides the lipid layer thickness increase obtained from theophthalmic suspension as set forth in Table 1. Table 17 provides thelipid layer thickness increase obtained from the Systane® Ultra PFsolution.

Clear separation of the test and control drops at every time point areillustrated, with the ophthalmic suspension showing a nearly 50%increase in lipid layer thickness at the 4-hour mark. Thus, reduction inlipid layer thickness is delayed to well beyond the 4-hour mark beforereturning to baseline. If the degradation rate remains linear, asignificant lipid layer thickness increase is likely to extend wellbeyond 8 hours using only a single drop of the ophthalmic suspension.

TABLE 16 Ophthalmic Suspension Increase In Percentage Increase TimeLipid Layer in Lipid Layer Interval Thickness (nm) Thickness  5 Minutes29.7 59.9%  30 Minutes 28.1 56.7%  60 Minutes 20.7 41.8% 120 Minutes24.5 49.5% 180 Minutes 20.9 42.3% 240 Minutes 23.0 46.5%

TABLE 17 Systane ® Ultra Increase In Percentage Increase Time LipidLayer in Lipid Layer Interval Thickness (nm) Thickness  5 Minutes 9.215.9%  30 Minutes 8.6 14.9%  60 Minutes 3.7  6.4% 120 Minutes 3.5  6.1%180 Minutes 5.9 10.4% 240 Minutes 4.2  7.4%

Two subjective questions were asked to patients immediately upon dropinstillation for each eye. The first question asked patients to scoretheir initial comfort from 0-100. The second question was to report theduration of any visual blurring they noticed. For the ophthalmicsuspension, the average patient noted an 85 out of 100 comfort score and5.6 seconds of minimal visual blurring. For the control drop the averageresults were 92 out of 100 and 2.9 seconds. While there is a differenceon both metrics between test and control, blurring was less than 3seconds longer for the ophthalmic suspension, while initial comfortscore varied by 7 out of 100.

Most patients reported no blurring for the ophthalmic suspension, withthe longest blur duration was 30 seconds (one in test eye and one incontrol eye). The patient comfort scores were similar and ranged from 45to 100 in the test eye and 50 to 100 in the control eye. Based onthousands of hours of in-house testing, the comfort and blur are similarto the control solution.

A self-administered SPEED dry eye symptom questionnaire was incorporatedinto this study. A score of 8 or greater indicated the presence of dryeye. Patients responded with an average SPEED score of 13.58 at thebeginning of the test, prior to drop instillation. All patients testedreported initial SPEED scores of greater than 8.

After 4 hours elapsed after drop instillation, patients were re-testedusing SPEED. The average result for the post assessment was a score of10.5, with no patients reporting an increased score and five patientsreporting a score of less than 8. The assessment did not distinguishsymptoms between eyes. Since the experiment was conducted incontralateral eyes, the delineating effect of the ophthalmic suspensionversus the control drops was difficult. The SPEED assessment was meantto gauge symptoms over a span of weeks or months, so an immediate resultmay not be an accurate reflection of the patient's symptoms. Finally,the time of day was a variable not controlled for in this study and mayhave had an effect on patient-reported symptoms.

In summary, this study demonstrated a significant increase in lipidlayer thickness relative to control over a four-hour interval in anarms-length, physician-administered study. Particularly, the ophthalmicdemonstrated a nearly 50% increase in lipid layer thickness at the4-hour mark in a controlled on-eye patient evaluation thereby resultingin a decrease in patient reported dry eye symptoms. These benefits wereobserved without significant implications relative to initial dropcomfort and visual blurring.

While not being bound to a particularly theory, as wax ester particlesare dissolving, the oil bound with the wax ester particles is believedto be released into the tear film and migrates to the surface,continuously replenishing the patient's diminished evaporative lipidbarrier. Differently-sized particles dissolve at different rates. Ineffect, the wide distribution of oil-bound wax ester particles creates acontrolled-release mechanism that delivers lipids into the tear filmwith every blink as the wax ester particle is dissolved. The wax esteris believed to act as a mechanism to slow the lipid layer from drainingthrough the puncta during the course of regular tear turnover.

Example 6 Ophthalmic Suspensions Compared to Commercial Artificial Tears

A study was conducted to evaluate the on-eye performance of theophthalmic suspension as set forth in Table 1 versus differentcommercially available artificial tear products (HyloCare®, Tears Again,Cationorm®, Hylovision®, Thealoz®, EvoTears®, TheraTears®, Systane®Complete, Systane® Balance, Soothe®XP, Retaine® MGD and Refresh Optive®Advanced).

Lipid layer thickness measurements of the commercial products were takenout to 60 minutes. The ophthalmic suspension was measured to 120 minutesand beyond. The testing was open-label and utilized Systane Ultra PF® asthe control. A total of 93 observations (n=93) among the 12 commerciallyavailable products were made. The results show that no product was ableto increase lipid layer thickness 13 nm over the control at the 5-minutetime interval, and the best performing commercial product showed anincrease in 10 nm over control at the 60-minute time interval.

On average, an increase in 21 nm over the control at the 5-minute timeinterval with the lipid layer thickness continuing to increase to 24.7nm at the 60-minute time point (n=78). The aggregated data is summarizedin Tables 18 and 19.

TABLE 18 Ophthalmic Suspension (n = 78) Increase In Time Lipid LayerThickness Interval (nm) From Baseline  5 Minutes 20 30 Minutes 24 60Minutes 23

TABLE 19 Commercial Product (n = 93) Increase In Time Lipid LayerThickness Interval (nm) From Baseline  5 Minutes 5 30 Minutes 3 60Minutes 2

In aggregate, the ophthalmic suspensions showed a five times (5×)improvement in immediate lipid layer thickness increase over 78cumulative observations compared with the 93 cumulative observations ofthe 12 commercially available products. This gap in lipid layerthickness increase is eleven times (11×) at the 60-minute mark with theophthalmic suspension showing a 23 nm increase over baseline relative tocontrol versus the commercial products only showing a two nm increaseover baseline relative to control.

Example 7 Tear Film Stability

A wax ester containing oil-in-water suspension was compared to severalother commercially available products.

A beeswax containing ophthalmic suspension: H714: 5.0 Dr-21, 10.0% Bee'sMilk (Beeswax, Sesame Oil, Lecithin, Methyl Paraben, and Water) (KosterKeunen), 0.18 Tween-80, 0.1 EDTA, and b.a./NaCl to 100 mOsm.

Water soluble polymer solution #1: *DUASORB* (polymeric systemcontaining 0.1% Dextran 70, 0.3% hydroxypropyl methylcellulose 2910),0.001% polyquaternium-1, sodium borate, KCl, NaCl, H₂O, and HCl and/orNaOH.

Tear film performance was evaluated using the standard contralateral eyeexperiments by observation of the interference patterns. In terms ofmethod of delivery, a standard full drop of approximately 50 μL wasdelivered to the eyes of five subjects.

Wax-ester formulation H714 versus to water soluble polymer solution #1:H714 performed very well in the interference analysis of tear filmthickness. Initially, H714 scored 2.5 grades above baseline for thefirst two hours and returning to baseline after three hours. In one setof experiments the water soluble polymer solution, on the other hand,was 2.0 grades above baseline initially but faded quite rapidly within30 minutes. In another set of experiments, after instillation both theH714 and the water soluble polymer were at about 1.8 grades abovebaseline. After 15 minutes water soluble polymer solution #1 wentvirtually back to baseline, while H714 (˜1% beeswax) remained on the eyefor over two hours. The water soluble polymer #1 which showed an initiala 2.0 score change showed a return to essentially baseline at 1 hour.(see FIG. 2 ).

Example 8 Zeta Potential and Ionic Mobility Analysis

Zeta potential testing was conducted to evaluate particle performanceand stability of various ophthalmic suspensions versus an ophthalmicdrop commercially available as Systane® Balance. Zeta potentialindicates the degree of electrostatic repulsion between similarlycharged particles in a dispersion. In general, a high negative zetapotential correlates to stability (e.g., a dispersion will resistaggregation). In the ophthalmic context, the applicant has demonstrateda higher negative potential directly translates to longer dwell time ofan ophthalmic suspension on the eye.

Ionic mobility testing was conducted on the same ophthalmic suspensionsand Systane® Balance eye drop to evaluate the particle velocitygenerated by an electric field.

The content of the ophthalmic suspensions tested (samples A-F) are showin Table 20. Sample A was homogenized at a speed of 10,000 RPM for twominutes with beeswax added into the aqueous phase. Sample B washomogenized at a speed of 20,000 RPM for eight minutes with beeswaxadded into the aqueous phase. Samples C and D were homogenized at aspeed of 18,000 RPM for eight minutes with beeswax added into theaqueous phase. Samples E and F were homogenized at a speed of 18,000 RPMfor eight minutes with beeswax added into the oil phase with the oil andwater phases separated and tested. The Systane® Balance eye dropincluded propylene glycol (0.6%) lubricant as the primary activeingredient along with various inactive ingredients including boric acid,dimyristoylphosphatidylglycerol, edetate disodium, hydroxypropyl guar,mineral oil, polyoxyl 40 stearate, POLYQUAD® (polyquaternium-1) 0.001%preservative, sorbitan tristearate, sorbitol and purified water, as wellas hydrochloric acid and/or sodium hydroxide to adjust pH.

The results of the zeta potential and ionic mobility testing areprovided in Table 21.

TABLE 20 Component Weight (% w/w) Sample A B C D E F Water 91.65 91.3791.67 91.67 91.67 91.67 NaCl 0.67 0.55 0.55 0.55 0.55 0.55 NaH2PO4 0.030.03 0.03 0.03 0.03 0.03 Na2HPO4 0.25 0.25 0.25 0.25 0.25 0.25 Tween-800.4 0.6 0.4 0.4 0.4 0.4 DMPG 0.4 0.6 0.5 0.5 0.5 0.5 Beeswax 1 1 1 1 1 1HA 0.1 0.1 0.1 0.1 0.1 0.1 Drakeol ® - 35 4.5 4.5 4.5 4.5 4.5 4.5Drakeol ® - 15 1 1 1 1 1 1

TABLE 21 ζ μ Potential Ionic Mobility Sample (mV) (μm/s)/(V/cm) A −76−5.9 B −94 −7.4 C −80 −6.3 D −93 −7.2 E −81 −6.3 F −90 −7.1 Systane ®Balance  −6 −0.5

Ophthalmic suspensions A-F all demonstrated a zeta potential of fromabout −75 to about −95 and an ionic mobility of from about −6 to about−7.5. These results demonstrate that ophthalmic suspensions as providedherein provide sizable stabilization of large particles as well assustained thickening of tear film, unlike that of the Systane® Balanceeye drop which demonstrated markedly different zeta potential and ionicmobility.

Example 9 Suspension Separation

A preparation of the formula in Table 1 was allowed to stand for aminimum of two hours. The formulation showed separation of thesuspension showing different regions as an oil phase to a water phase.The formulation was then stained using solid Oil Red dye whichpreferentially stains the oil in the formulation which is a hydrocarbonoil but does not stain the wax ester component. Microscopic observationof the phases show the different regions of the separated productincluding the oil phase that contains mineral oil with discreteunstained wax particles primarily with estimated particle size of 200 to500 nm with some larger particle greater than two microns. Sample of thepreparation were separated into the oil phase and aqueous phase. Eachwas tested in eyes with the results showing that the particle associatedwith the oil phase showed the primary activity associated with extensionof time that the product enhanced the lipid layer thickness.

Example 10 USP (87) Biological Reactivity Testing—Benzalkonium Chloride(BAK)

Testing was conducted by a neutral third party laboratory to determinethe cytotoxicity of benzalkonium chloride (BAK) when used as apreservative in a standard topical saline ophthalmic solution vehicle.Test solutions of BAK at various dilutions at the typical preservationconcentration used in ophthalmic products (50 ppm) were subject to USP(87) biological reactivity testing and graded according to reactivity.All solutions contained EDTA as an adjunct to enable the BAK to beactive against gram negative bacteria. All negative and positivecontrols were nominal. All test solutions were graded as exhibiting“severe” reactivity meaning there was nearly complete destruction of allcell layers and therefore use of BAK did not meet USP requirements.Thus, in conclusion, BAK (with EDTA) at concentrations 5% of the “useconcentration” in typical ophthalmic products caused severe reactivityaccording to the USP (87) biological reactivity test.

It should be understood that the above description is onlyrepresentative of illustrative embodiments and examples. For theconvenience of the reader, the above description has focused on alimited number of representative examples of all possible embodiments,examples that teach the principles of the disclosure. The descriptionhas not attempted to exhaustively enumerate all possible variations oreven combinations of those variations described. That alternateembodiments may not have been presented for a specific portion of thedisclosure, or that further undescribed alternate embodiments may beavailable for a portion, is not to be considered a disclaimer of thosealternate embodiments. One of ordinary skill will appreciate that manyof those undescribed embodiments, involve differences in technology andmaterials rather than differences in the application of the principlesof the disclosure. Accordingly, the disclosure is not intended to belimited to less than the scope set forth in the following claims andequivalents.

It is to be understood that, while the disclosure has been described inconjunction with the detailed description, thereof, the foregoingdescription is intended to illustrate and not limit the scope. Otheraspects, advantages, and modifications are within the scope of theclaims set forth below.

Generalized Statements of the Disclosure

The following numbered statements provide a general description of thedisclosure and are not intended to limit the appended claims.

Statement 1. An ophthalmic suspension is provided that includes: i) anaqueous phase comprising water and one or more components selected fromthe group consisting of at least one wax ester, at least one anionicpolar surfactant, at least one nonionic surfactant, at least one salt,and at least one phosphate; and ii) an oil phase comprising at least onemineral oil and, optionally, at least one wax ester. The wax esterexhibits a mean particle size of at least about 5.0 microns using aMicrotrac particle analyzer procedure to determine particle size.

Statement 2. The present disclosure provides an ophthalmic emulsifiedsuspension of Statement 1.

Statement 3. The present disclosure provides an ophthalmic suspension ofany of Statements 1-2, wherein the ophthalmic suspension has anosmolality of from about 245 mOsmol/kg to about 315 mOsmol/kg.

Statement 4. The present disclosure provides an ophthalmic suspension ofany of Statements 1-3, wherein the ophthalmic suspension is formulatedas a free flowing emulsified suspension at about 30° C.

Statement 5. The present disclosure provides an ophthalmic suspension ofany of Statements 1-4, wherein the wax ester is present in aconcentration of about 0.8 weight percent to about 1.2 weight percent.

Statement 6. The present disclosure provides an ophthalmic suspension ofany of Statements 1-5, wherein the wax ester is a natural beeswax.

Statement 7. The present disclosure provides an ophthalmic suspension ofany of Statements 1-6, wherein the ophthalmic suspension exhibits anegative zeta potential of from about −60 mV to about −110 mV.

Statement 8. The present disclosure provides an ophthalmic suspension ofany of Statements 1-7, wherein the ophthalmic suspension exhibits anionic mobility of from about −5.9 (μms)/(V/cm) to about −7.4(μms)/(V/cm).

Statement 9. The present disclosure provides an ophthalmic suspension ofany of Statements 1-8, wherein the oil is a mixture of a lightweightmineral oil and a heavy weight mineral oil.

Statement 10. The present disclosure provides an ophthalmic suspensionof any of Statements 1-9, wherein the lightweight mineral oil exhibits akinetic viscosity of from about 3.0 mm²s⁻¹ to about 34.4 mm²s⁻¹ at 40°C. and the heavy weight mineral oil exhibits a viscosity of kineticviscosity of from about 34.5 mm²s⁻¹ to about 150 mm²s⁻¹ at 40° C.

Statement 11. The present disclosure provides an ophthalmic suspensionof any of Statements 1-10, further including an anionic polar surfactantcomprising a mixture of a polysorbate non-ionic surfactant at aconcentration of about 0.35 to about 0.45 weight percent and an anionicpolar dimyristoylphosphatidylglycerol at a concentration of about 0.35to about 0.55 weight percent.

Statement 12. The present disclosure provides an ophthalmic suspensionof any of Statements 1-11, packaged in a sterile multi-use or sterilesingle use container.

Statement 13. The present disclosure provides an ophthalmic suspensionof any of Statements 1-12, packaged in a multi-dose non-preserved (MDNP)container or a container including at least one preservative.

Statement 14. The present disclosure provides an ophthalmic suspensionof any of Statements 1-13, wherein ophthalmic suspension increases lipidlayer thickness by at least 20 nanometers at five minutes afteradministration.

Statement 15. The present disclosure provides an ophthalmic suspensionof any of Statements 1-14, wherein the ophthalmic suspension increaseslipid layer thickness by at least 20 nanometers at four hours afteradministration.

Statement 16. A method of increasing lipid layer thickness is providedand includes the step of administering an ophthalmic suspension of anyof Statements 1-15 to an eye of a patient in need of treatment.

Statement 17. The present disclosure provides a method of increasinglipid layer thickness of Statement 16, wherein the lipid layer thicknessis increased by at least 20 nm within five minutes of administration.

Statement 18. The present disclosure provides a method of increasinglipid layer thickness of any of Statements 16-17, wherein the lipidlayer thickness is increased by at least 20 nm at four hour afteradministration.

Statement 19. The present disclosure provides a method of lubricating aneye including administering to the eye an ophthalmic suspension of anyof Statements 1-15 to an eye of a patient in need of treatment.

Statement 20. The present disclosure provides a method of foralleviating the symptoms of dry eye including administering to the eyean ophthalmic suspension of any of Statements 1-15 to an eye of apatient in need of treatment.

Statement 21. An ophthalmic suspension is provided that includes a waxdispersion including (a) water; (b) at least one oil; (c) a surfactant;and (d) at least one wax ester present in a concentration of about 0.5to about 1.5 weight percent. The at least one wax ester in theophthalmic suspension binds a mucin layer, an aqueous layer, and a lipidlayer in an eye of a subject and act to maintain or enhance theintegrity of an interstitial layer between the mucin layer and theaqueous layer, and interstitial layer between the aqueous layer and thelipid layer.

Statement 22. The present disclosure provides an ophthalmic solution ofStatement 21, wherein the at least one wax ester acts to increase thethickness of the mucin layer, the aqueous layer, the lipid layer, or acombination thereof.

Statement 23. The present disclosure provides an ophthalmic suspensionof any of Statements 21-22, wherein binding and homeostasis enabled bythe wax, wax esters or hydrolysis products allows the mucin layer, theaqueous layer and the lipid layer of a tear film to interact with toeach other allowing the tear film to remain on the eye for extendedperiods of time (e.g., at least two hours).

Statement 24. An ophthalmic suspension is provided that exhibits a zetapotential of from about −60 mV to about −110 mV.

Statement 25. An ophthalmic suspension is provided that forms a metastable emulsion which separates into an oil phase and a water phase oncontact with an eye and provides lubrication for about 2 to about 12hours on the eye.

Statement 26. A method for alleviating the symptoms of dry eye isprovided which includes the step of contacting an eye with an ophthalmicsuspension of any of Statements 21-25.

Statement 27. The present disclosure provides a method alleviating thesymptoms of dry eye of Statement 26, wherein on contact with an eye theophthalmic suspension interacts with: a lipid layer; an aqueous layer; amucin layer; an interface between the lipid layer and the aqueous layer;and an interface between the aqueous layer and the mucin layer of theeye and unprotected corneal cells.

Statement 28. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-27, where the wax ester ofthe ophthalmic suspension is a natural beeswax or a synthetic beeswax.

Statement 29. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-28, wherein the oil is amixture of a lighter weight mineral oil and a heavier mineral weightoil.

Statement 30. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-29, wherein the oil ispresent in a concentration of about 1.0 weight percent to about 5 weightpercent.

Statement 31. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-30, wherein the surfactantis a mixture of two or more surfactants.

Statement 32. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-31, wherein (i) the oil is amixture of a lighter weight oil and a heavier weight oil and is presentin a concentration of about 1.0 to about 5.5 weight percent; (ii) thesurfactant is a mixture of a Polysorbate 80 in a concentration of about0.35 to about 0.45 weight percent and a dimyristoylphosphatidylglycerolin a concentration of about 0.3 to about 0.5 weight percent; (iii) thewax ester is a natural or a synthetic beeswax present in a concentrationof about 0.5 to about 1.0 weight percent; and the ophthalmic suspensionhas an osmolality of about 245 to about 310 mOsmol/kg.

Statement 33. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-32, wherein the ophthalmicsuspension is packaged in a sterile multi-use or sterile single usecontainer.

Statement 34. The present disclosure provides a method alleviating thesymptoms of dry eye of any of Statements 26-33, wherein the ophthalmicsuspension is packaged in a multi-dose non-preserved (MDNP) container ora container including at least one preservative.

Statement 35. The present disclosure provides a method of preparing anophthalmic suspension that includes the steps of: (a) preparing a waxester and a surfactant in a purified or deionized water suspension; (b)preparing an oil-in-water emulsion comprising an oil in a purified ordeionized water suspension; (c) separately autoclaving the beeswaxdispersion and the oil-in-water emulsion; (d) and aseptically blendingthe autoclaved beeswax dispersion and the oil-in-water emulsion so as toprepare the meta stable oil-in-water emulsion ophthalmic suspension.

Statement 36. The present disclosure provides a method of preparing anophthalmic suspension of Statement 35, wherein the ophthalmic solutionprovides lubrication for at least about 2 hours on the eye.

Statement 37. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-36, wherein the ophthalmicsolution provides lubrication for at least about 12 hours on the eye.

Statement 38. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-37, wherein on contactwith an eye the ophthalmic suspension penetrates: a lipid layer; anaqueous layer; a mucin layer; an interface between the lipid layer andthe aqueous layer; and an interface between the aqueous layer and themucin layer of the eye and unprotected corneal cells.

Statement 39. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-38, wherein the wax esteris a natural beeswax.

Statement 40. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-39, wherein the beeswax isa synthetic beeswax

Statement 41. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-40, wherein the oil is amixture of a lighter weight oil and a heavier weight oil.

Statement 42. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-41, wherein the surfactantis a mixture of two or more surfactants.

Statement 43. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-42, wherein (i) the oil isa mixture of a light weight oil and a heavy weight oil and is present ina concentration of about 1.0 to about 5.5 weight percent; (ii) thesurfactant is a mixture of a Polysorbate 80 in a concentration of about0.35 to about 0.45 weight percent and a dimyristoylphosphatidylglycerolin a concentration of about 0.3 to about 0.5 weight percent; (iii) thewax ester is a natural beeswax or a synthetic beeswax present in aconcentration of about 0.25 to about 1.0 weight percent; and theophthalmic suspension has an osmolality of about 245 to about 310mOsmol/kg.

Statement 44. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-43, wherein the ophthalmicsuspension is packaged in a sterile multi-use or sterile single usecontainer.

Statement 45. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-44, wherein the ophthalmicsuspension is packaged in a multi-dose non-preserved (MDNP) container ora container including at least one preservative.

Statement 46. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-44, wherein the ophthalmicsuspension is packaged in a container containing a preservative.

Statement 47. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-46, wherein the wax estersact to increase the thickness of the mucin layer, the aqueous layer, thelipid layer, or a combination thereof.

Statement 48. The present disclosure provides a method of preparing anophthalmic suspension of any of Statements 35-47, wherein binding andhomeostasis enabled by the wax esters allows the mucin layer, theaqueous layer and the lipid layer of a tear film to interact with eachother allowing the tear film to remain on the eye for at least twohours.

Statement 49. The present disclosure provides a method of preparing anophthalmic suspension that includes the steps of: (a) preparing an oilphase; (b) preparing the aqueous phase; (c) mixing the oil phase andaqueous phase to form the ophthalmic suspension; (d) and autoclaving theophthalmic suspension.

Statement 50. The present disclosure provides a method of preparing anophthalmic suspension of Statement 49, wherein the step of preparing theoil phase (e.g., heavy weight mineral oil and light weight mineral oil)includes heating to a temperature of from about 63° C. to about 71° C.

Statement 51. The present disclosure provides a method of preparing anophthalmic suspension of Statements 49-50, wherein the step of preparingthe oil phase includes the step of adding or introducing at least onewax ester to the oil phase followed by heating the mixture to atemperature above the melting point of the wax ester (e.g., from about63° C. to about 71° C.).

Statement 52. The present disclosure provides a method of preparing anophthalmic suspension of Statements 49-51, wherein the aqueous phase maybe prepared by mixing the at least one wax ester, at least one salt, atleast one phosphate, at least one surfactant and any other water-solubleingredient followed by heating the mixture to a temperature above themelting point of the wax ester (e.g., from about 63° C. to about 71°C.).

Statement 53. The present disclosure provides a method of preparing anophthalmic suspension of Statements 49-52, wherein the individual oilphase and aqueous phase are not separately autoclaved prior to beingcombined.

Statement 54. The present disclosure provides an ophthalmic suspensionconsisting of:

-   -   a wax dispersion comprising natural beeswax particles, an        anionic polar surfactant and water;    -   sodium hyaluronate; and    -   an oil-in-water emulsion comprising an oil and water; and    -   optionally, at least one preservative selected from the group        consisting of polyhexamethylene biguanide, stabilized oxychloro        complex and polyquaternium-1, wherein:    -   (i) the oil is a mixture of a lighter molecular weight mineral        oil and a heavier molecular weight mineral oil and is present in        a concentration of about 4.0 to about 6.25 weight percent;    -   (ii) the anionic polar surfactant is a mixture of a Polysorbate        80 in a concentration of about 0.35 to about 0.45 weight percent        and an anionic polar dimyristoylphosphatidylglyerol in a        concentration of about 0.35 to about 0.50 weight percent; and    -   (iii) the natural beeswax particles are solid up to about 60° C.        and are present in a concentration of about 0.50 to about 1.25        weight percent; and    -   wherein the ophthalmic suspension vehicle:        -   (i) forms a meta stable emulsion which separates into an oil            phase and a water phase on contact with an eye;        -   (ii) provides a dwell time on the eye of at least two hours;        -   (iii) is formulated as a free flowing liquid at room            temperature;        -   (iv) has an osmolality of about 230 mOsmol/kg to about 260            mOsmol/kg; and        -   (v) has a pH of from about 6.5 to about 7.8.

Statement 55. The present disclosure provides an ophthalmic suspensionof Statement 54, wherein the beeswax is present in a concentration ofabout 1.0 weight percent.

Statement 56. The present disclosure provides an ophthalmic suspensionof Statements 54-55, wherein the beeswax is Cera Alba or Cera Flava.

Statement 57. The present disclosure provides an ophthalmic suspensionof Statements 1-56, packaged in a sterile single use container.

Statement 58. The present disclosure provides an ophthalmic suspensionof Statements 1-56, packaged in a sterile multi-dose container.

Statement 59. The present disclosure provides a finished pharmaceuticalproduct comprising the ophthalmic suspension vehicle of Statements 1-56.

Statement 60. The present disclosure provides a finished pharmaceuticalproduct comprising the ophthalmic suspension vehicle of Statements 1-56.

Statement 61. The present disclosure provides a finished pharmaceuticalproduct comprising the ophthalmic suspension vehicle of Statements 1-56.

What is claimed is:
 1. A method of maintaining integrity of an eye'stear film layers which increases the eye's lipid layer thickness, themethod comprising the step of: administering an ophthalmic suspension toan eye of a patient in need of treatment, the ophthalmic suspensioncomprising: i) an aqueous phase comprising water and one or morecomponents selected from the group consisting of at least one wax ester,at least one anionic polar surfactant, at least one nonionic surfactant,at least one salt, and at least one phosphate; and ii) an oil phasecomprising at least one mineral oil and, optionally, at least one waxester, wherein the ophthalmic suspension exhibits a Zeta potential offrom about −60 mV to about −110 mV.
 2. The method of claim 1, whereinthe integrity of the tear film is maintained and lipid layer thicknessis increased by at least 20 nm at 60 minutes after administration. 3.The method of claim 1, wherein the ophthalmic suspension has anosmolality of from about 245 mOsmol/kg to about 310 mOsmol/kg.
 4. Themethod of claim 1, wherein the ophthalmic suspension is formulated as afree flowing emulsified suspension at about 30° C.
 5. The method ofclaim 1, wherein the ophthalmic suspension includes a total wax estercontent of about 0.8 weight percent to about 1.2 weight percent.
 6. Themethod of claim 1, wherein the ophthalmic suspension exhibits an ionicmobility of from about −5.9 (μms)/(V/cm) to about −7.4 (μms)/(V/cm). 7.The method of claim 1, wherein the oil is a mixture of a lightweightmineral oil and a heavy weight mineral oil.
 8. The method of claim 7,wherein the lightweight mineral oil exhibits a kinetic viscosity of fromabout 3.0 mm²s⁻¹ to about 34.4 mm²s⁻¹ at 40° C. and the heavy weightmineral oil exhibits a viscosity of kinetic viscosity of from about 34.5mm²s⁻¹ to about 150 mm²s⁻¹ at 40° C.
 9. The method of claim 1, furthercomprising an anionic polar surfactant comprising a mixture of apolysorbate non-ionic surfactant at a concentration of about 0.35 toabout 0.45 weight percent and an anionic polardimyristoylphosphatidylglycerol at a concentration of about 0.35 toabout 0.55 weight percent.
 10. The method of claim 1, packaged in asterile multi-use or sterile single use container.
 11. The method ofclaim 1, packaged in a multi-dose non-preserved (MDNP) container or acontainer including at least one preservative.
 12. The method of claim1, wherein the ophthalmic suspension increases lipid layer thickness byat least 20 nanometers at 60 minutes after administration.
 13. Themethod of claim 1, wherein the ophthalmic suspension increases lipidlayer thickness by at least 20 nanometers at two hours afteradministration.
 14. The method of claim 1, wherein the ophthalmicsuspension further comprises hyaluronic acid, a corresponding hyaluronicacid sodium salt, sodium hyaluronate, or any combination thereof.
 15. Amethod of recreating or building one or more layers of an eye's tearfilm comprising the step of: administering an ophthalmic suspension toan eye of a patient in need of treatment, the ophthalmic suspensioncomprising i) an aqueous phase comprising water and one or morecomponents selected from the group consisting of at least one wax ester,at least one anionic polar surfactant, at least one nonionic surfactant,at least one salt, and at least one phosphate; and ii) an oil phasecomprising at least one mineral oil and, optionally, at least one waxester, wherein, upon administration, the ophthalmic suspension recreatesor rebuilds the one or more layers of the eye's tear film, and whereinthe ophthalmic suspension exhibits a Zeta potential of from about −60 mVto about −110 mV.
 16. The method of claim 15, wherein the ophthalmicsuspension further comprises hyaluronic acid, a corresponding hyaluronicacid sodium salt, sodium hyaluronate, or any combination thereof.
 17. Amethod for lubricating an eye comprising the step of: administering anophthalmic suspension to an eye of a patient in need of treatment, theophthalmic suspension comprising: i) an aqueous phase comprising waterand one or more components selected from the group consisting of atleast one wax ester, at least one anionic polar surfactant, at least onenonionic surfactant, at least one salt, and at least one phosphate; andii) an oil phase comprising at least one mineral oil and, optionally, atleast one wax ester, wherein, upon administration, the ophthalmicsuspension recreates or rebuilds one or more layers of the eye's tearfilm and maintains integrity of the tear film for over 60 minutes, andwherein the ophthalmic suspension exhibits a Zeta potential of fromabout −60 mV to about −110 mV.
 18. The method of claim 17, wherein theophthalmic suspension further comprises hyaluronic acid, a correspondinghyaluronic acid sodium salt, sodium hyaluronate, or any combinationthereof.